20815976736 has 72 divisors (see below), whose sum is σ = 59254928460. Its totient is φ = 6931685376.

The previous prime is 20815976717. The next prime is 20815976761. The reversal of 20815976736 is 63767951802.

It can be written as a sum of positive squares in 2 ways, for example, as 19087080336 + 1728896400 = 138156^2 + 41580^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 254776 + ... + 326408.

Almost surely, 2^20815976736 is an apocalyptic number.

It is an amenable number.

20815976736 is an abundant number, since it is smaller than the sum of its proper divisors (38438951724).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20815976736 is a wasteful number, since it uses less digits than its factorization.

20815976736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72658 (or 72647 counting only the distinct ones).

The product of its (nonzero) digits is 3810240, while the sum is 54.

The spelling of 20815976736 in words is "twenty billion, eight hundred fifteen million, nine hundred seventy-six thousand, seven hundred thirty-six".