21285524 has 12 divisors (see below), whose sum is σ = 40115124. Its totient is φ = 9824064.

The previous prime is 21285521. The next prime is 21285569. The reversal of 21285524 is 42558212.

It can be written as a sum of positive squares in 2 ways, for example, as 7728400 + 13557124 = 2780^2 + 3682^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21285521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 204617 + ... + 204720.

It is an arithmetic number, because the mean of its divisors is an integer number (3342927).

Almost surely, 2^21285524 is an apocalyptic number.

It is an amenable number.

21285524 is a deficient number, since it is larger than the sum of its proper divisors (18829600).

21285524 is a wasteful number, since it uses less digits than its factorization.

21285524 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 409354 (or 409352 counting only the distinct ones).

The product of its digits is 6400, while the sum is 29.

The square root of 21285524 is about 4613.6237384512. The cubic root of 21285524 is about 277.1371726511.

The spelling of 21285524 in words is "twenty-one million, two hundred eighty-five thousand, five hundred twenty-four".