15995561551 has 2 divisors, whose sum is σ = 15995561552. Its totient is φ = 15995561550.

The previous prime is 15995561509. The next prime is 15995561591. The reversal of 15995561551 is 15516559951.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 15995561551 - 2²⁵ = 15962007119 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15995561591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7997780775 + 7997780776.

It is an arithmetic number, because the mean of its divisors is an integer number (7997780776).

Almost surely, 2^15995561551 is an apocalyptic number.

15995561551 is a deficient number, since it is larger than the sum of its proper divisors (1).

15995561551 is an equidigital number, since it uses as much as digits as its factorization.

15995561551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1518750, while the sum is 52.

The spelling of 15995561551 in words is "fifteen billion, nine hundred ninety-five million, five hundred sixty-one thousand, five hundred fifty-one".