20990721732 has 24 divisors (see below), whose sum is σ = 51556159200. Its totient is φ = 6628648896.

The previous prime is 20990721707. The next prime is 20990721757. The reversal of 20990721732 is 23712709902.

It is an interprime number because it is at equal distance from previous prime (20990721707) and next prime (20990721757).

It is a super-2 number, since 2×20990721732² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46032057 + ... + 46032512.

It is an arithmetic number, because the mean of its divisors is an integer number (2148173300).

Almost surely, 2^20990721732 is an apocalyptic number.

It is an amenable number.

20990721732 is an abundant number, since it is smaller than the sum of its proper divisors (30565437468).

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

20990721732 is a wasteful number, since it uses less digits than its factorization.

20990721732 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92064595 (or 92064593 counting only the distinct ones).

The product of its (nonzero) digits is 95256, while the sum is 42.

The spelling of 20990721732 in words is "twenty billion, nine hundred ninety million, seven hundred twenty-one thousand, seven hundred thirty-two".