21398922 has 24 divisors (see below), whose sum is σ = 47126820. Its totient is φ = 7015680.

The previous prime is 21398917. The next prime is 21398941. The reversal of 21398922 is 22989312.

It can be written as a sum of positive squares in 2 ways, for example, as 13995081 + 7403841 = 3741^2 + 2721^2 .

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, 8647 + ... + 10842.

Almost surely, 2^21398922 is an apocalyptic number.

21398922 is an abundant number, since it is smaller than the sum of its proper divisors (25727898).

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

21398922 is a wasteful number, since it uses less digits than its factorization.

21398922 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19558 (or 19555 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 21398922 is about 4625.8968860103. The cubic root of 21398922 is about 277.6284479618.

The spelling of 21398922 in words is "twenty-one million, three hundred ninety-eight thousand, nine hundred twenty-two".