Number of the day: 75991

Thomas Joannes Stieltjes was born on this day 164 years ago.

Properties of the number 75991:

75991 is a cyclic number.
75989 and 75991 form a twin prime pair.
75991 has 19 antidivisors and 75990 totatives.
75991 has an emirp digit sum 31 in base 10.
Reversing the decimal digits of 75991 results in a semiprime.
75991 = 37996² - 37995² is the difference of 2 nonnegative squares in 1 way.
75991 is the sum of 2 positive triangular numbers.
75991 is the difference of 2 positive pentagonal numbers in 1 way.
75991 is not the sum of 3 positive squares.
75991² is the sum of 3 positive squares.
75991 is a proper divisor of 1531⁴⁴⁷ - 1.
75991 is an emirp in (at least) the following bases: 3, 5, 9, 11, 14, 15, 16, 20, 23, 28, 29, 34, 35, 39, 42, 49, 51, 57, 59, 63, 65, 75, 77, 79, 83, 91, 93, and 99.
75991 in base 49 = VVf and consists of only the digits 'V' and 'f'.

The number 75991 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A096510: a(n) is the smallest number x such that the number of prime powers (including primes, excluding 1), in the neighborhood of x with radius ceiling(log(x)), equals n.
A096518: Solutions to A096509[x]=7; number of prime-powers [including primes] in the neighborhood of x with Ceiling[Log[x]] radius equals 7.
A106301: Primes that do not divide any term of the Lucas 5-step sequence A074048.
A135843: Prime numbers p of the form 10k+1 for which the pentanacci quintic polynomial x^5-x^4-x^3-x^2-x-1 modulus p is factorizable into five binomials.