21052525 has 24 divisors (see below), whose sum is σ = 28338464. Its totient is φ = 15422400.

The previous prime is 21052489. The next prime is 21052547. The reversal of 21052525 is 52525012.

It is a de Polignac number, because none of the positive numbers 2^k-21052525 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21052496 and 21052505.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 68422 + ... + 68728.

Almost surely, 2^21052525 is an apocalyptic number.

21052525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21052525 is a deficient number, since it is larger than the sum of its proper divisors (7285939).

21052525 is a wasteful number, since it uses less digits than its factorization.

21052525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 541 (or 536 counting only the distinct ones).

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

The square root of 21052525 is about 4588.3030632250. The cubic root of 21052525 is about 276.1222459588.

Adding to 21052525 its reverse (52525012), we get a palindrome (73577537).

The spelling of 21052525 in words is "twenty-one million, fifty-two thousand, five hundred twenty-five".