21640019976 has 48 divisors (see below), whose sum is σ = 58617409500. Its totient is φ = 7212229632.

The previous prime is 21640019971. The next prime is 21640019977. The reversal of 21640019976 is 67991004612.

It can be written as a sum of positive squares in 2 ways, for example, as 12348987876 + 9291032100 = 111126^2 + 96390^2 .

It is not an unprimeable number, because it can be changed into a prime (21640019971) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 543600 + ... + 582048.

Almost surely, 2^21640019976 is an apocalyptic number.

It is an amenable number.

21640019976 is an abundant number, since it is smaller than the sum of its proper divisors (36977389524).

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

21640019976 is a wasteful number, since it uses less digits than its factorization.

21640019976 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46278 (or 46271 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 45.

The spelling of 21640019976 in words is "twenty-one billion, six hundred forty million, nineteen thousand, nine hundred seventy-six".