21937938 has 16 divisors (see below), whose sum is σ = 47864736. Its totient is φ = 6647840.

The previous prime is 21937931. The next prime is 21937943. The reversal of 21937938 is 83973912.

It is a super-3 number, since 3×21937938³ (a number of 23 digits) contains 333 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21937938.

It is not an unprimeable number, because it can be changed into a prime (21937931) 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, 166131 + ... + 166262.

It is an arithmetic number, because the mean of its divisors is an integer number (2991546).

Almost surely, 2^21937938 is an apocalyptic number.

21937938 is an abundant number, since it is smaller than the sum of its proper divisors (25926798).

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

21937938 is a wasteful number, since it uses less digits than its factorization.

21937938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332409.

The product of its digits is 81648, while the sum is 42.

The square root of 21937938 is about 4683.7952559863. The cubic root of 21937938 is about 279.9401998143.

The spelling of 21937938 in words is "twenty-one million, nine hundred thirty-seven thousand, nine hundred thirty-eight".