21664292 has 12 divisors (see below), whose sum is σ = 40828956. Its totient is φ = 9998880.

The previous prime is 21664267. The next prime is 21664297. The reversal of 21664292 is 29246612.

It can be written as a sum of positive squares in 2 ways, for example, as 7929856 + 13734436 = 2816^2 + 3706^2 .

It is a super-2 number, since 2×21664292² = 938683095722528, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21664297) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 208259 + ... + 208362.

It is an arithmetic number, because the mean of its divisors is an integer number (3402413).

Almost surely, 2^21664292 is an apocalyptic number.

It is an amenable number.

21664292 is a deficient number, since it is larger than the sum of its proper divisors (19164664).

21664292 is a wasteful number, since it uses less digits than its factorization.

21664292 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 416638 (or 416636 counting only the distinct ones).

The product of its digits is 10368, while the sum is 32.

The square root of 21664292 is about 4654.4915941486. The cubic root of 21664292 is about 278.7713683874.

The spelling of 21664292 in words is "twenty-one million, six hundred sixty-four thousand, two hundred ninety-two".