20518738525 has 24 divisors (see below), whose sum is σ = 25613840520. Its totient is φ = 16305104640.

The previous prime is 20518738483. The next prime is 20518738529. The reversal of 20518738525 is 52583781502.

It can be written as a sum of positive squares in 12 ways, for example, as 6390563481 + 14128175044 = 79941^2 + 118862^2 .

It is not a de Polignac number, because 20518738525 - 2¹¹ = 20518736477 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20518738529) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8947279 + ... + 8949571.

It is an arithmetic number, because the mean of its divisors is an integer number (1067243355).

Almost surely, 2^20518738525 is an apocalyptic number.

20518738525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20518738525 is a deficient number, since it is larger than the sum of its proper divisors (5095101995).

20518738525 is a wasteful number, since it uses less digits than its factorization.

20518738525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4545 (or 4540 counting only the distinct ones).

The product of its (nonzero) digits is 672000, while the sum is 46.

The spelling of 20518738525 in words is "twenty billion, five hundred eighteen million, seven hundred thirty-eight thousand, five hundred twenty-five".