21365304 has 16 divisors (see below), whose sum is σ = 53413320. Its totient is φ = 7121760.

The previous prime is 21365303. The next prime is 21365347. The reversal of 21365304 is 40356312.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (24), and also a Moran number because the ratio is a prime number: 890221 = 21365304 / (2 + 1 + 3 + 6 + 5 + 3 + 0 + 4).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21365303) 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, 445087 + ... + 445134.

Almost surely, 2^21365304 is an apocalyptic number.

21365304 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21365304 is an abundant number, since it is smaller than the sum of its proper divisors (32048016).

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

21365304 is a wasteful number, since it uses less digits than its factorization.

21365304 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 890230 (or 890226 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 24.

The square root of 21365304 is about 4622.2617840187. The cubic root of 21365304 is about 277.4829857274.

The spelling of 21365304 in words is "twenty-one million, three hundred sixty-five thousand, three hundred four".