21893994 has 24 divisors (see below), whose sum is σ = 50228100. Its totient is φ = 6868608.

The previous prime is 21893987. The next prime is 21894013. The reversal of 21893994 is 49939812.

It can be written as a sum of positive squares in 2 ways, for example, as 21762225 + 131769 = 4665^2 + 363^2 .

It is a congruent number.

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, 35469 + ... + 36080.

Almost surely, 2^21893994 is an apocalyptic number.

21893994 is an abundant number, since it is smaller than the sum of its proper divisors (28334106).

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

21893994 is a wasteful number, since it uses less digits than its factorization.

21893994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71574 (or 71571 counting only the distinct ones).

The product of its digits is 139968, while the sum is 45.

The square root of 21893994 is about 4679.1018368913. The cubic root of 21893994 is about 279.7531583042.

The spelling of 21893994 in words is "twenty-one million, eight hundred ninety-three thousand, nine hundred ninety-four".