15631015561 has 4 divisors (see below), whose sum is σ = 17864017792. Its totient is φ = 13398013332.

The previous prime is 15631015549. The next prime is 15631015571. The reversal of 15631015561 is 16551013651.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 15631015561 - 2⁵ = 15631015529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15631015571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1116501105 + ... + 1116501118.

It is an arithmetic number, because the mean of its divisors is an integer number (4466004448).

Almost surely, 2^15631015561 is an apocalyptic number.

It is an amenable number.

15631015561 is a deficient number, since it is larger than the sum of its proper divisors (2233002231).

15631015561 is an equidigital number, since it uses as much as digits as its factorization.

15631015561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2233002230.

The product of its (nonzero) digits is 13500, while the sum is 34.

The spelling of 15631015561 in words is "fifteen billion, six hundred thirty-one million, fifteen thousand, five hundred sixty-one".