21356004 has 24 divisors (see below), whose sum is σ = 50515360. Its totient is φ = 7020864.

The previous prime is 21356003. The next prime is 21356047. The reversal of 21356004 is 40065312.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21356003) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11314 + ... + 13065.

Almost surely, 2^21356004 is an apocalyptic number.

It is an amenable number.

21356004 is an abundant number, since it is smaller than the sum of its proper divisors (29159356).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21356004 is a wasteful number, since it uses less digits than its factorization.

21356004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24459 (or 24457 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 21356004 is about 4621.2556735156. The cubic root of 21356004 is about 277.4427184746.

The spelling of 21356004 in words is "twenty-one million, three hundred fifty-six thousand, four".