21413988 has 36 divisors (see below), whose sum is σ = 56980560. Its totient is φ = 6762096.

The previous prime is 21413971. The next prime is 21413993. The reversal of 21413988 is 88931412.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14970 + ... + 16337.

Almost surely, 2^21413988 is an apocalyptic number.

It is an amenable number.

21413988 is an abundant number, since it is smaller than the sum of its proper divisors (35566572).

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

21413988 is a wasteful number, since it uses less digits than its factorization.

21413988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31336 (or 31331 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 21413988 is about 4627.5250404509. The cubic root of 21413988 is about 277.6935878312.

The spelling of 21413988 in words is "twenty-one million, four hundred thirteen thousand, nine hundred eighty-eight".