21525025 has 6 divisors (see below), whose sum is σ = 26691062. Its totient is φ = 17220000.

The previous prime is 21525017. The next prime is 21525059. The reversal of 21525025 is 52052512.

It can be written as a sum of positive squares in 3 ways, for example, as 5914624 + 15610401 = 2432^2 + 3951^2 .

It is not a de Polignac number, because 21525025 - 2³ = 21525017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21524987 and 21525005.

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, 430476 + ... + 430525.

Almost surely, 2^21525025 is an apocalyptic number.

21525025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21525025 is a deficient number, since it is larger than the sum of its proper divisors (5166037).

21525025 is an equidigital number, since it uses as much as digits as its factorization.

21525025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 861011 (or 861006 counting only the distinct ones).

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

The square root of 21525025 is about 4639.5069781174. The cubic root of 21525025 is about 278.1727313610.

Adding to 21525025 its reverse (52052512), we get a palindrome (73577537).

The spelling of 21525025 in words is "twenty-one million, five hundred twenty-five thousand, twenty-five".