21938320 has 40 divisors (see below), whose sum is σ = 53228736. Its totient is φ = 8393088.

The previous prime is 21938269. The next prime is 21938327. The reversal of 21938320 is 2383912.

It is a tau number, because it is divible by the number of its divisors (40).

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (21938327) 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, 4122 + ... + 7801.

Almost surely, 2^21938320 is an apocalyptic number.

21938320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21938320 is an abundant number, since it is smaller than the sum of its proper divisors (31290416).

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

21938320 is a wasteful number, since it uses less digits than its factorization.

21938320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11959 (or 11953 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 21938320 is about 4683.8360347049. The cubic root of 21938320 is about 279.9418246485.

The spelling of 21938320 in words is "twenty-one million, nine hundred thirty-eight thousand, three hundred twenty".