21364664 has 16 divisors (see below), whose sum is σ = 42167400. Its totient is φ = 10120032.

The previous prime is 21364661. The next prime is 21364669. The reversal of 21364664 is 46646312.

It is a self number, because there is not a number n which added to its sum of digits gives 21364664.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21364661) 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, 70127 + ... + 70430.

Almost surely, 2^21364664 is an apocalyptic number.

It is an amenable number.

21364664 is a deficient number, since it is larger than the sum of its proper divisors (20802736).

21364664 is a wasteful number, since it uses less digits than its factorization.

21364664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140582 (or 140578 counting only the distinct ones).

The product of its digits is 20736, while the sum is 32.

The square root of 21364664 is about 4622.1925533236. The cubic root of 21364664 is about 277.4802150221.

The spelling of 21364664 in words is "twenty-one million, three hundred sixty-four thousand, six hundred sixty-four".