21367684 has 36 divisors (see below), whose sum is σ = 41140596. Its totient is φ = 9704448.

The previous prime is 21367681. The next prime is 21367699. The reversal of 21367684 is 48676312.

It can be written as a sum of positive squares in 6 ways, for example, as 6390784 + 14976900 = 2528^2 + 3870^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21367681) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 49132 + ... + 49564.

Almost surely, 2^21367684 is an apocalyptic number.

It is an amenable number.

21367684 is a deficient number, since it is larger than the sum of its proper divisors (19772912).

21367684 is a wasteful number, since it uses less digits than its factorization.

21367684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 536 (or 521 counting only the distinct ones).

The product of its digits is 48384, while the sum is 37.

The square root of 21367684 is about 4622.5192265690. The cubic root of 21367684 is about 277.4932888023.

The spelling of 21367684 in words is "twenty-one million, three hundred sixty-seven thousand, six hundred eighty-four".