15995561591 has 2 divisors, whose sum is σ = 15995561592. Its totient is φ = 15995561590.

The previous prime is 15995561551. The next prime is 15995561599. The reversal of 15995561591 is 19516559951.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 15995561591 - 2³⁰ = 14921819767 is a prime.

It is a super-2 number, since 2×15995561591² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15995561599) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7997780795 + 7997780796.

It is an arithmetic number, because the mean of its divisors is an integer number (7997780796).

Almost surely, 2^15995561591 is an apocalyptic number.

15995561591 is a deficient number, since it is larger than the sum of its proper divisors (1).

15995561591 is an equidigital number, since it uses as much as digits as its factorization.

15995561591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2733750, while the sum is 56.

The spelling of 15995561591 in words is "fifteen billion, nine hundred ninety-five million, five hundred sixty-one thousand, five hundred ninety-one".