21316504 has 32 divisors (see below), whose sum is σ = 46170000. Its totient is φ = 9118720.

The previous prime is 21316501. The next prime is 21316507. The reversal of 21316504 is 40561312.

It is an interprime number because it is at equal distance from previous prime (21316501) and next prime (21316507).

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21316501) 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, 5629 + ... + 8620.

Almost surely, 2^21316504 is an apocalyptic number.

It is an amenable number.

21316504 is an abundant number, since it is smaller than the sum of its proper divisors (24853496).

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

21316504 is a wasteful number, since it uses less digits than its factorization.

21316504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14283 (or 14279 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 21316504 is about 4616.9799653020. The cubic root of 21316504 is about 277.2715605042.

Adding to 21316504 its reverse (40561312), we get a palindrome (61877816).

The spelling of 21316504 in words is "twenty-one million, three hundred sixteen thousand, five hundred four".