21552525 has 18 divisors (see below), whose sum is σ = 38603370. Its totient is φ = 11494560.

The previous prime is 21552521. The next prime is 21552529. The reversal of 21552525 is 52525512.

It is an interprime number because it is at equal distance from previous prime (21552521) and next prime (21552529).

It can be written as a sum of positive squares in 3 ways, for example, as 594441 + 20958084 = 771^2 + 4578^2 .

It is not a de Polignac number, because 21552525 - 2² = 21552521 is a prime.

It is a super-2 number, since 2×21552525² = 929022667751250, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21552521) 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 17 ways as a sum of consecutive naturals, for example, 47670 + ... + 48119.

Almost surely, 2^21552525 is an apocalyptic number.

21552525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21552525 is a deficient number, since it is larger than the sum of its proper divisors (17050845).

21552525 is a wasteful number, since it uses less digits than its factorization.

21552525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95805 (or 95797 counting only the distinct ones).

The product of its digits is 5000, while the sum is 27.

The square root of 21552525 is about 4642.4697091096. The cubic root of 21552525 is about 278.2911438397.

The spelling of 21552525 in words is "twenty-one million, five hundred fifty-two thousand, five hundred twenty-five".