15520323681 has 8 divisors (see below), whose sum is σ = 22993072160. Its totient is φ = 10346882436.

The previous prime is 15520323677. The next prime is 15520323703. The reversal of 15520323681 is 18632302551.

15520323681 is a `hidden beast` number, since 1 + 552 + 0 + 3 + 23 + 6 + 81 = 666.

It is not a de Polignac number, because 15520323681 - 2² = 15520323677 is a prime.

It is a super-2 number, since 2×15520323681² (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 (15520323601) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 287413375 + ... + 287413428.

It is an arithmetic number, because the mean of its divisors is an integer number (2874134020).

Almost surely, 2^15520323681 is an apocalyptic number.

It is an amenable number.

15520323681 is a deficient number, since it is larger than the sum of its proper divisors (7472748479).

15520323681 is an equidigital number, since it uses as much as digits as its factorization.

15520323681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 574826812 (or 574826806 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The spelling of 15520323681 in words is "fifteen billion, five hundred twenty million, three hundred twenty-three thousand, six hundred eighty-one".