20931904920 has 64 divisors (see below), whose sum is σ = 64492909920. Its totient is φ = 5430979584.

The previous prime is 20931904907. The next prime is 20931904949. The reversal of 20931904920 is 2940913902.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2352757 + ... + 2361636.

Almost surely, 2^20931904920 is an apocalyptic number.

20931904920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20931904920 is an abundant number, since it is smaller than the sum of its proper divisors (43561005000).

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

20931904920 is a wasteful number, since it uses less digits than its factorization.

20931904920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4714444 (or 4714440 counting only the distinct ones).

The product of its (nonzero) digits is 34992, while the sum is 39.

The spelling of 20931904920 in words is "twenty billion, nine hundred thirty-one million, nine hundred four thousand, nine hundred twenty".