15818997872 has 20 divisors (see below), whose sum is σ = 31168790040. Its totient is φ = 7775439168.

The previous prime is 15818997863. The next prime is 15818997911. The reversal of 15818997872 is 27879981851.

It is a junction number, because it is equal to n+sod(n) for n = 15818997799 and 15818997808.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8377763 + ... + 8379650.

It is an arithmetic number, because the mean of its divisors is an integer number (1558439502).

Almost surely, 2^15818997872 is an apocalyptic number.

It is an amenable number.

15818997872 is a deficient number, since it is larger than the sum of its proper divisors (15349792168).

15818997872 is a wasteful number, since it uses less digits than its factorization.

15818997872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16757480 (or 16757474 counting only the distinct ones).

The product of its digits is 20321280, while the sum is 65.

The spelling of 15818997872 in words is "fifteen billion, eight hundred eighteen million, nine hundred ninety-seven thousand, eight hundred seventy-two".