Number of the day: 1087

Properties of the number 1087:

1087 is a cyclic number.
1087 is the 181^th prime.
1087 has 13 antidivisors and 1086 totatives.
Reversing the decimal digits of 1087 results in a semiprime.
1087 = 544² - 543² is the difference of 2 nonnegative squares in 1 way.
1087 is the sum of 2 positive triangular numbers.
1087 is the difference of 2 positive pentagonal numbers in 1 way.
1087 is not the sum of 3 positive squares.
1087² is the sum of 3 positive squares.
1087 is a proper divisor of 257³ - 1.
1087 = '10' + '87' is the concatenation of 2 semiprime numbers.
1087 is an emirp in (at least) the following bases: 2, 6, 13, 14, 15, 17, 19, 21, 25, 28, 29, 30, 34, 35, 37, 40, 41, 42, 43, 49, 50, 53, 56, 59, 61, 62, 67, 73, 75, 81, 83, 92, 94, 95, 97, and 99.
1087 is palindromic in (at least) the following bases: 12, -11, and -31.
1087 in base 12 = 767 and consists of only the digits '6' and '7'.
1087 in base 32 = 11v and consists of only the digits '1' and 'v'.

The number 1087 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A006450: Prime-indexed primes: primes with prime subscripts.
A007522: Primes of the form 8n+7, that is, primes congruent to -1 mod 8.
A008483: Number of partitions of n into parts >= 3.
A008865: a(n) = n^2 - 2.
A022005: Initial members of prime triples (p, p+4, p+6).
A023200: Primes p such that p + 4 is also prime.
A107132: Primes of the form 2x^2 + 13y^2.
A139643: Primes of the form x^2+Ny^2, with N=102.
A140633: Primes of the form 7x^2+4xy+52y^2.
A235482: Primes whose base-5 representation is also the base-9 representation of a prime.