21525013025 has 6 divisors (see below), whose sum is σ = 26691016182. Its totient is φ = 17220010400.

The previous prime is 21525013019. The next prime is 21525013039. The reversal of 21525013025 is 52031052512.

It can be written as a sum of positive squares in 3 ways, for example, as 3707835664 + 17817177361 = 60892^2 + 133481^2 .

It is not a de Polignac number, because 21525013025 - 2²⁸ = 21256577569 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21525012985 and 21525013003.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 430500236 + ... + 430500285.

It is an arithmetic number, because the mean of its divisors is an integer number (4448502697).

Almost surely, 2^21525013025 is an apocalyptic number.

21525013025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21525013025 is a deficient number, since it is larger than the sum of its proper divisors (5166003157).

21525013025 is an equidigital number, since it uses as much as digits as its factorization.

21525013025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 861000531 (or 861000526 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 26.

Adding to 21525013025 its reverse (52031052512), we get a palindrome (73556065537).

The spelling of 21525013025 in words is "twenty-one billion, five hundred twenty-five million, thirteen thousand, twenty-five".