21458764 has 12 divisors (see below), whose sum is σ = 37719864. Its totient is φ = 10681664.

The previous prime is 21458741. The next prime is 21458797. The reversal of 21458764 is 46785412.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10909 + ... + 12724.

It is an arithmetic number, because the mean of its divisors is an integer number (3143322).

Almost surely, 2^21458764 is an apocalyptic number.

It is an amenable number.

21458764 is a deficient number, since it is larger than the sum of its proper divisors (16261100).

21458764 is a wasteful number, since it uses less digits than its factorization.

21458764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23864 (or 23862 counting only the distinct ones).

The product of its digits is 53760, while the sum is 37.

The square root of 21458764 is about 4632.3605213757. The cubic root of 21458764 is about 277.8870027112.

It can be divided in two parts, 21458 and 764, that added together give a palindrome (22222).

The spelling of 21458764 in words is "twenty-one million, four hundred fifty-eight thousand, seven hundred sixty-four".