21358408 has 8 divisors (see below), whose sum is σ = 40047030. Its totient is φ = 10679200.

The previous prime is 21358399. The next prime is 21358429. The reversal of 21358408 is 80485312.

It can be written as a sum of positive squares in only one way, i.e., 17123044 + 4235364 = 4138^2 + 2058^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 21358408.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1334893 + ... + 1334908.

Almost surely, 2^21358408 is an apocalyptic number.

It is an amenable number.

21358408 is a deficient number, since it is larger than the sum of its proper divisors (18688622).

21358408 is a wasteful number, since it uses less digits than its factorization.

21358408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2669807 (or 2669803 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 31.

The square root of 21358408 is about 4621.5157686629. The cubic root of 21358408 is about 277.4531284632.

The spelling of 21358408 in words is "twenty-one million, three hundred fifty-eight thousand, four hundred eight".