21331324 has 12 divisors (see below), whose sum is σ = 42662704. Its totient is φ = 9141984.

The previous prime is 21331313. The next prime is 21331333. The reversal of 21331324 is 42313312.

21331324 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 380889 + ... + 380944.

Almost surely, 2^21331324 is an apocalyptic number.

It is an amenable number.

21331324 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21331324 is a wasteful number, since it uses less digits than its factorization.

21331324 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 761844 (or 761842 counting only the distinct ones).

The product of its digits is 432, while the sum is 19.

The square root of 21331324 is about 4618.5846316810. The cubic root of 21331324 is about 277.3358020049.

Adding to 21331324 its reverse (42313312), we get a palindrome (63644636).

The spelling of 21331324 in words is "twenty-one million, three hundred thirty-one thousand, three hundred twenty-four".