21317304 has 32 divisors (see below), whose sum is σ = 54170640. Its totient is φ = 6988800.

The previous prime is 21317267. The next prime is 21317327. The reversal of 21317304 is 40371312.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5817 + ... + 8744.

Almost surely, 2^21317304 is an apocalyptic number.

21317304 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21317304 is an abundant number, since it is smaller than the sum of its proper divisors (32853336).

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

21317304 is a wasteful number, since it uses less digits than its factorization.

21317304 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14631 (or 14627 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 21.

The square root of 21317304 is about 4617.0666012090. The cubic root of 21317304 is about 277.2750290917.

Adding to 21317304 its reverse (40371312), we get a palindrome (61688616).

The spelling of 21317304 in words is "twenty-one million, three hundred seventeen thousand, three hundred four".