21456525 has 24 divisors (see below), whose sum is σ = 35969920. Its totient is φ = 11283840.

The previous prime is 21456521. The next prime is 21456563. The reversal of 21456525 is 52565412.

It is not a de Polignac number, because 21456525 - 2² = 21456521 is a prime.

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

Its product of digits (12000) is a multiple of the sum of its prime divisors (4000).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21456492 and 21456501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21456521) 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 23 ways as a sum of consecutive naturals, for example, 3516 + ... + 7434.

Almost surely, 2^21456525 is an apocalyptic number.

21456525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21456525 is a deficient number, since it is larger than the sum of its proper divisors (14513395).

21456525 is a wasteful number, since it uses less digits than its factorization.

21456525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4005 (or 4000 counting only the distinct ones).

The product of its digits is 12000, while the sum is 30.

The square root of 21456525 is about 4632.1188456256. The cubic root of 21456525 is about 277.8773374972.

The spelling of 21456525 in words is "twenty-one million, four hundred fifty-six thousand, five hundred twenty-five".