Tuesday, October 16, 2018

Number of the day: 701

Properties of the number 701:

701 is a cyclic number.
701 is the 126th prime.
701 has 5 antidivisors and 700 totatives.
701 has a Fibonacci digit sum 8 in base 10.
701 has sum of divisors equal to 702 which is an oblong number.
Reversing the decimal digits of 701 results in an emirp.
701 = 43 + 53 + 83 is the sum of 3 positive cubes in 1 way.
701 = 3512 - 3502 is the difference of 2 nonnegative squares in 1 way.
701 is the difference of 2 positive pentagonal numbers in 1 way.
701 = 52 + 262 is the sum of 2 positive squares in 1 way.
701 = 122 + 142 + 192 is the sum of 3 positive squares.
7012 = 2602 + 6512 is the sum of 2 positive squares in 1 way.
7012 is the sum of 3 positive squares.
701 is a proper divisor of 895 - 1.
701 = '70' + '1' is the concatenation of 2 pentagonal numbers.
701 is an emirp in (at least) the following bases: 2, 3, 7, 10, 11, 14, 17, 23, 24, 26, 27, 28, 30, 36, 39, 40, 41, 46, 51, 55, 59, 67, 69, 73, 76, 83, 87, 88, 89, 90, 93, 94, 96, 97, and 100.
701 is palindromic in (at least) the following bases: 5, 9, 20, 25, -5, -7, -12, -28, -35, -50, -70, and -100.
701 in base 3 = 221222 and consists of only the digits '1' and '2'.
701 in base 9 = 858 and consists of only the digits '5' and '8'.
701 in base 11 = 588 and consists of only the digits '5' and '8'.
701 in base 18 = 22h and consists of only the digits '2' and 'h'.
701 in base 19 = 1hh and consists of only the digits '1' and 'h'.
701 in base 20 = 1f1 and consists of only the digits '1' and 'f'.
701 in base 24 = 155 and consists of only the digits '1' and '5'.
701 in base 25 = 131 and consists of only the digits '1' and '3'.

The number 701 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A000978: Wagstaff numbers: numbers n such that (2^n + 1)/3 is prime.
A001122: Primes with primitive root 2.
A006567: Emirps (primes whose reversal is a different prime).
A007500: Primes whose reversal in base 10 is also prime (called "palindromic primes" by D. Wells, although that name usually refers to A002385). Also called reversible primes.
A028387: a(n) = n + (n+1)^2.
A030430: Primes of the form 10*n+1.
A034856: a(n) = binomial(n+1, 2) + n - 1 = n(n + 3)/2 - 1.
A139827: Primes of the form 2x^2+2xy+17y^2.
A192476: Monotonic ordering of set S generated by these rules: if x and y are in S then x^2 + y^2 is in S, and 1 is in S.
A235394: Primes whose decimal representation is a valid number in base 8 and interpreted as such is again a prime.

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