21025525 has 6 divisors (see below), whose sum is σ = 26071682. Its totient is φ = 16820400.

The previous prime is 21025513. The next prime is 21025561. The reversal of 21025525 is 52552012.

It can be written as a sum of positive squares in 3 ways, for example, as 5963364 + 15062161 = 2442^2 + 3881^2 .

It is not a de Polignac number, because 21025525 - 2⁷ = 21025397 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21025496 and 21025505.

It is a congruent number.

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, 420486 + ... + 420535.

Almost surely, 2^21025525 is an apocalyptic number.

21025525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21025525 is a deficient number, since it is larger than the sum of its proper divisors (5046157).

21025525 is an equidigital number, since it uses as much as digits as its factorization.

21025525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 841031 (or 841026 counting only the distinct ones).

The product of its (nonzero) digits is 1000, while the sum is 22.

The square root of 21025525 is about 4585.3598550168. The cubic root of 21025525 is about 276.0041526015.

Adding to 21025525 its reverse (52552012), we get a palindrome (73577537).

The spelling of 21025525 in words is "twenty-one million, twenty-five thousand, five hundred twenty-five".