21971698 has 12 divisors (see below), whose sum is σ = 38338542. Its totient is φ = 9416400.

The previous prime is 21971687. The next prime is 21971707. The reversal of 21971698 is 89617912.

It can be written as a sum of positive squares in only one way, i.e., 21930489 + 41209 = 4683^2 + 203^2 .

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 5 ways as a sum of consecutive naturals, for example, 112003 + ... + 112198.

Almost surely, 2^21971698 is an apocalyptic number.

21971698 is a deficient number, since it is larger than the sum of its proper divisors (16366844).

21971698 is a wasteful number, since it uses less digits than its factorization.

21971698 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224217 (or 224210 counting only the distinct ones).

The product of its digits is 54432, while the sum is 43.

The square root of 21971698 is about 4687.3977855522. The cubic root of 21971698 is about 280.0837249623.

It can be divided in two parts, 219 and 71698, that added together give a palindrome (71917).

The spelling of 21971698 in words is "twenty-one million, nine hundred seventy-one thousand, six hundred ninety-eight".