21368168 has 8 divisors (see below), whose sum is σ = 40065330. Its totient is φ = 10684080.

The previous prime is 21368153. The next prime is 21368177. The reversal of 21368168 is 86186312.

It can be written as a sum of positive squares in only one way, i.e., 17455684 + 3912484 = 4178^2 + 1978^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1335503 + ... + 1335518.

Almost surely, 2^21368168 is an apocalyptic number.

It is an amenable number.

21368168 is a deficient number, since it is larger than the sum of its proper divisors (18697162).

21368168 is a wasteful number, since it uses less digits than its factorization.

21368168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2671027 (or 2671023 counting only the distinct ones).

The product of its digits is 13824, while the sum is 35.

The square root of 21368168 is about 4622.5715786778. The cubic root of 21368168 is about 277.4953839559.

The spelling of 21368168 in words is "twenty-one million, three hundred sixty-eight thousand, one hundred sixty-eight".