21938930 has 16 divisors (see below), whose sum is σ = 42528024. Its totient is φ = 8100480.

The previous prime is 21938923. The next prime is 21938947. The reversal of 21938930 is 3983912.

It can be written as a sum of positive squares in 4 ways, for example, as 10896601 + 11042329 = 3301^2 + 3323^2 .

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, 84251 + ... + 84510.

Almost surely, 2^21938930 is an apocalyptic number.

21938930 is a deficient number, since it is larger than the sum of its proper divisors (20589094).

21938930 is a wasteful number, since it uses less digits than its factorization.

21938930 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168781.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 21938930 is about 4683.9011518178. The cubic root of 21938930 is about 279.9444192399.

The spelling of 21938930 in words is "twenty-one million, nine hundred thirty-eight thousand, nine hundred thirty".