21192664 has 8 divisors (see below), whose sum is σ = 39736260. Its totient is φ = 10596328.

The previous prime is 21192643. The next prime is 21192671. The reversal of 21192664 is 46629112.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1324534 + ... + 1324549.

Almost surely, 2^21192664 is an apocalyptic number.

It is an amenable number.

21192664 is a deficient number, since it is larger than the sum of its proper divisors (18543596).

21192664 is a wasteful number, since it uses less digits than its factorization.

21192664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2649089 (or 2649085 counting only the distinct ones).

The product of its digits is 5184, while the sum is 31.

The square root of 21192664 is about 4603.5490656666. The cubic root of 21192664 is about 276.7335732768.

The spelling of 21192664 in words is "twenty-one million, one hundred ninety-two thousand, six hundred sixty-four".