21938680 has 32 divisors (see below), whose sum is σ = 49541040. Its totient is φ = 8743680.

The previous prime is 21938663. The next prime is 21938699. The reversal of 21938680 is 8683912.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12412 + ... + 14068.

Almost surely, 2^21938680 is an apocalyptic number.

21938680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21938680 is an abundant number, since it is smaller than the sum of its proper divisors (27602360).

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

21938680 is a wasteful number, since it uses less digits than its factorization.

21938680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1999 (or 1995 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 21938680 is about 4683.8744645859. The cubic root of 21938680 is about 279.9433558886.

The spelling of 21938680 in words is "twenty-one million, nine hundred thirty-eight thousand, six hundred eighty".