21488764 has 12 divisors (see below), whose sum is σ = 41024088. Its totient is φ = 9767600.

The previous prime is 21488759. The next prime is 21488801. The reversal of 21488764 is 46788412.

It is a congruent number.

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, 244147 + ... + 244234.

It is an arithmetic number, because the mean of its divisors is an integer number (3418674).

Almost surely, 2^21488764 is an apocalyptic number.

It is an amenable number.

21488764 is a deficient number, since it is larger than the sum of its proper divisors (19535324).

21488764 is a wasteful number, since it uses less digits than its factorization.

21488764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 488396 (or 488394 counting only the distinct ones).

The product of its digits is 86016, while the sum is 40.

The square root of 21488764 is about 4635.5974803686. The cubic root of 21488764 is about 278.0164405507.

The spelling of 21488764 in words is "twenty-one million, four hundred eighty-eight thousand, seven hundred sixty-four".