21331900 has 18 divisors (see below), whose sum is σ = 46290440. Its totient is φ = 8532720.

The previous prime is 21331897. The next prime is 21331901. The reversal of 21331900 is 913312.

It is a super-2 number, since 2×21331900² = 910099915220000, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21331901) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 106560 + ... + 106759.

Almost surely, 2^21331900 is an apocalyptic number.

21331900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21331900 is an abundant number, since it is smaller than the sum of its proper divisors (24958540).

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

21331900 is a wasteful number, since it uses less digits than its factorization.

21331900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213333 (or 213326 counting only the distinct ones).

The product of its (nonzero) digits is 162, while the sum is 19.

The square root of 21331900 is about 4618.6469880258. The cubic root of 21331900 is about 277.3382982397.

The spelling of 21331900 in words is "twenty-one million, three hundred thirty-one thousand, nine hundred".