21525513525 has 36 divisors (see below), whose sum is σ = 39494959140. Its totient is φ = 11200262400.

The previous prime is 21525513521. The next prime is 21525513533. The reversal of 21525513525 is 52531552512.

21525513525 is a `hidden beast` number, since 2 + 1 + 52 + 551 + 3 + 52 + 5 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 1507225329 + 20018288196 = 38823^2 + 141486^2 .

It is not a de Polignac number, because 21525513525 - 2² = 21525513521 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21525513525.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21525513521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1157470 + ... + 1175919.

Almost surely, 2^21525513525 is an apocalyptic number.

21525513525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21525513525 is a deficient number, since it is larger than the sum of its proper divisors (17969445615).

21525513525 is a wasteful number, since it uses less digits than its factorization.

21525513525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2333446 (or 2333438 counting only the distinct ones).

The product of its digits is 75000, while the sum is 36.

The spelling of 21525513525 in words is "twenty-one billion, five hundred twenty-five million, five hundred thirteen thousand, five hundred twenty-five".