21363904 has 28 divisors (see below), whose sum is σ = 44627800. Its totient is φ = 10119168.

The previous prime is 21363899. The next prime is 21363907. The reversal of 21363904 is 40936312.

It is not an unprimeable number, because it can be changed into a prime (21363907) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7569 + ... + 10000.

It is an arithmetic number, because the mean of its divisors is an integer number (1593850).

Almost surely, 2^21363904 is an apocalyptic number.

It is an amenable number.

21363904 is an abundant number, since it is smaller than the sum of its proper divisors (23263896).

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

21363904 is a wasteful number, since it uses less digits than its factorization.

21363904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17600 (or 17590 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 28.

The square root of 21363904 is about 4622.1103405263. The cubic root of 21363904 is about 277.4769247376.

The spelling of 21363904 in words is "twenty-one million, three hundred sixty-three thousand, nine hundred four".