21124525 has 12 divisors (see below), whose sum is σ = 26387200. Its totient is φ = 16775280.

The previous prime is 21124501. The next prime is 21124529. The reversal of 21124525 is 52542112.

It is not a de Polignac number, because 21124525 - 2²¹ = 19027373 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21124496 and 21124505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21124529) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 436 + ... + 6514.

Almost surely, 2^21124525 is an apocalyptic number.

21124525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21124525 is a deficient number, since it is larger than the sum of its proper divisors (5262675).

21124525 is a wasteful number, since it uses less digits than its factorization.

21124525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6228 (or 6223 counting only the distinct ones).

The product of its digits is 800, while the sum is 22.

The square root of 21124525 is about 4596.1424042342. The cubic root of 21124525 is about 276.4366687410.

Adding to 21124525 its reverse (52542112), we get a palindrome (73666637).

The spelling of 21124525 in words is "twenty-one million, one hundred twenty-four thousand, five hundred twenty-five".