15520972081 has 4 divisors (see below), whose sum is σ = 15524838000. Its totient is φ = 15517106164.

The previous prime is 15520972007. The next prime is 15520972097. The reversal of 15520972081 is 18027902551.

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 15520972081 - 2²⁷ = 15386754353 is a prime.

It is a super-2 number, since 2×15520972081² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15520972781) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1926931 + ... + 1934968.

It is an arithmetic number, because the mean of its divisors is an integer number (3881209500).

Almost surely, 2^15520972081 is an apocalyptic number.

It is an amenable number.

15520972081 is a deficient number, since it is larger than the sum of its proper divisors (3865919).

15520972081 is an equidigital number, since it uses as much as digits as its factorization.

15520972081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3865918.

The product of its (nonzero) digits is 50400, while the sum is 40.

The spelling of 15520972081 in words is "fifteen billion, five hundred twenty million, nine hundred seventy-two thousand, eighty-one".