21928868 has 12 divisors (see below), whose sum is σ = 41327580. Its totient is φ = 10120992.

The previous prime is 21928813. The next prime is 21928877. The reversal of 21928868 is 86882912.

It can be written as a sum of positive squares in 2 ways, for example, as 3541924 + 18386944 = 1882^2 + 4288^2 .

It is a super-2 number, since 2×21928868² = 961750503522848, which contains 22 as substring.

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 3 ways as a sum of consecutive naturals, for example, 210803 + ... + 210906.

It is an arithmetic number, because the mean of its divisors is an integer number (3443965).

Almost surely, 2^21928868 is an apocalyptic number.

It is an amenable number.

21928868 is a deficient number, since it is larger than the sum of its proper divisors (19398712).

21928868 is a wasteful number, since it uses less digits than its factorization.

21928868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 421726 (or 421724 counting only the distinct ones).

The product of its digits is 110592, while the sum is 44.

The square root of 21928868 is about 4682.8269239851. The cubic root of 21928868 is about 279.9016150939.

The spelling of 21928868 in words is "twenty-one million, nine hundred twenty-eight thousand, eight hundred sixty-eight".