21703664 has 20 divisors (see below), whose sum is σ = 42125280. Its totient is φ = 10832640.

The previous prime is 21703663. The next prime is 21703667. The reversal of 21703664 is 46630712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21703663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13832 + ... + 15320.

It is an arithmetic number, because the mean of its divisors is an integer number (2106264).

Almost surely, 2^21703664 is an apocalyptic number.

It is an amenable number.

21703664 is a deficient number, since it is larger than the sum of its proper divisors (20421616).

21703664 is a wasteful number, since it uses less digits than its factorization.

21703664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2408 (or 2402 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 29.

The square root of 21703664 is about 4658.7191372737. The cubic root of 21703664 is about 278.9401429468.

The spelling of 21703664 in words is "twenty-one million, seven hundred three thousand, six hundred sixty-four".