21723392 has 18 divisors (see below), whose sum is σ = 43362438. Its totient is φ = 10861568.

The previous prime is 21723389. The next prime is 21723397. The reversal of 21723392 is 29332712.

It can be written as a sum of positive squares in only one way, i.e., 16777216 + 4946176 = 4096^2 + 2224^2 .

It is not an unprimeable number, because it can be changed into a prime (21723397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42173 + ... + 42684.

Almost surely, 2^21723392 is an apocalyptic number.

It is an amenable number.

21723392 is a deficient number, since it is larger than the sum of its proper divisors (21639046).

21723392 is an frugal number, since it uses more digits than its factorization.

21723392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84873 (or 84859 counting only the distinct ones).

The product of its digits is 4536, while the sum is 29.

The square root of 21723392 is about 4660.8359765175. The cubic root of 21723392 is about 279.0246335140.

The spelling of 21723392 in words is "twenty-one million, seven hundred twenty-three thousand, three hundred ninety-two".