20639521570 has 16 divisors (see below), whose sum is σ = 37152804600. Its totient is φ = 8255438464.

The previous prime is 20639521561. The next prime is 20639521603. The reversal of 20639521570 is 7512593602.

It can be written as a sum of positive squares in 4 ways, for example, as 18096437529 + 2543084041 = 134523^2 + 50429^2 .

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, 347406 + ... + 402454.

Almost surely, 2^20639521570 is an apocalyptic number.

20639521570 is a deficient number, since it is larger than the sum of its proper divisors (16513283030).

20639521570 is a wasteful number, since it uses less digits than its factorization.

20639521570 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92549.

The product of its (nonzero) digits is 113400, while the sum is 40.

The spelling of 20639521570 in words is "twenty billion, six hundred thirty-nine million, five hundred twenty-one thousand, five hundred seventy".