21331844 has 12 divisors (see below), whose sum is σ = 38535168. Its totient is φ = 10321800.

The previous prime is 21331831. The next prime is 21331847. The reversal of 21331844 is 44813312.

It is not an unprimeable number, because it can be changed into a prime (21331847) 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 3 ways as a sum of consecutive naturals, for example, 85892 + ... + 86139.

It is an arithmetic number, because the mean of its divisors is an integer number (3211264).

Almost surely, 2^21331844 is an apocalyptic number.

It is an amenable number.

21331844 is a deficient number, since it is larger than the sum of its proper divisors (17203324).

21331844 is a wasteful number, since it uses less digits than its factorization.

21331844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172066 (or 172064 counting only the distinct ones).

The product of its digits is 2304, while the sum is 26.

The square root of 21331844 is about 4618.6409256404. The cubic root of 21331844 is about 277.3380555522.

The spelling of 21331844 in words is "twenty-one million, three hundred thirty-one thousand, eight hundred forty-four".