21739264 has 18 divisors (see below), whose sum is σ = 43394120. Its totient is φ = 10869504.

The previous prime is 21739261. The next prime is 21739303. The reversal of 21739264 is 46293712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21739261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42204 + ... + 42715.

Almost surely, 2^21739264 is an apocalyptic number.

It is an amenable number.

21739264 is a deficient number, since it is larger than the sum of its proper divisors (21654856).

21739264 is an frugal number, since it uses more digits than its factorization.

21739264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84935 (or 84921 counting only the distinct ones).

The product of its digits is 18144, while the sum is 34.

The square root of 21739264 is about 4662.5383644534. The cubic root of 21739264 is about 279.0925725791.

The spelling of 21739264 in words is "twenty-one million, seven hundred thirty-nine thousand, two hundred sixty-four".