20513513540 has 24 divisors (see below), whose sum is σ = 46392100440. Its totient is φ = 7574220288.

The previous prime is 20513513521. The next prime is 20513513593. The reversal of 20513513540 is 4531531502.

It can be written as a sum of positive squares in 4 ways, for example, as 3663396676 + 16850116864 = 60526^2 + 129808^2 .

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, 39448805 + ... + 39449324.

It is an arithmetic number, because the mean of its divisors is an integer number (1933004185).

Almost surely, 2^20513513540 is an apocalyptic number.

20513513540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20513513540 is an abundant number, since it is smaller than the sum of its proper divisors (25878586900).

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

20513513540 is a wasteful number, since it uses less digits than its factorization.

20513513540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78898151 (or 78898149 counting only the distinct ones).

The product of its (nonzero) digits is 9000, while the sum is 29.

The spelling of 20513513540 in words is "twenty billion, five hundred thirteen million, five hundred thirteen thousand, five hundred forty".