21938994 has 72 divisors (see below), whose sum is σ = 59754240. Its totient is φ = 5694480.

The previous prime is 21938971. The next prime is 21939007. The reversal of 21938994 is 49983912.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 14527 + ... + 15965.

It is an arithmetic number, because the mean of its divisors is an integer number (829920).

Almost surely, 2^21938994 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21938994, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29877120).

21938994 is an abundant number, since it is smaller than the sum of its proper divisors (37815246).

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

21938994 is a wasteful number, since it uses less digits than its factorization.

21938994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1476 (or 1462 counting only the distinct ones).

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

The square root of 21938994 is about 4683.9079837247. The cubic root of 21938994 is about 279.9446914565.

The spelling of 21938994 in words is "twenty-one million, nine hundred thirty-eight thousand, nine hundred ninety-four".