21372989 has 8 divisors (see below), whose sum is σ = 23423232. Its totient is φ = 19340640.

The previous prime is 21372977. The next prime is 21372991. The reversal of 21372989 is 98927312.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21372989 - 2²⁰ = 20324413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21372089) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1904 + ... + 6809.

It is an arithmetic number, because the mean of its divisors is an integer number (2927904).

Almost surely, 2^21372989 is an apocalyptic number.

It is an amenable number.

21372989 is a deficient number, since it is larger than the sum of its proper divisors (2050243).

21372989 is a wasteful number, since it uses less digits than its factorization.

21372989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8947.

The product of its digits is 54432, while the sum is 41.

The square root of 21372989 is about 4623.0930122592. The cubic root of 21372989 is about 277.5162515169.

The spelling of 21372989 in words is "twenty-one million, three hundred seventy-two thousand, nine hundred eighty-nine".