21973658 has 12 divisors (see below), whose sum is σ = 38341962. Its totient is φ = 9417240.

The previous prime is 21973649. The next prime is 21973681. The reversal of 21973658 is 85637912.

It can be written as a sum of positive squares in only one way, i.e., 21279769 + 693889 = 4613^2 + 833^2 .

It is a Curzon 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 5 ways as a sum of consecutive naturals, for example, 112013 + ... + 112208.

Almost surely, 2^21973658 is an apocalyptic number.

21973658 is a deficient number, since it is larger than the sum of its proper divisors (16368304).

21973658 is a wasteful number, since it uses less digits than its factorization.

21973658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224237 (or 224230 counting only the distinct ones).

The product of its digits is 90720, while the sum is 41.

The square root of 21973658 is about 4687.6068521155. The cubic root of 21973658 is about 280.0920530666.

The spelling of 21973658 in words is "twenty-one million, nine hundred seventy-three thousand, six hundred fifty-eight".