21313684 has 12 divisors (see below), whose sum is σ = 42627424. Its totient is φ = 9134424.

The previous prime is 21313679. The next prime is 21313693. The reversal of 21313684 is 48631312.

21313684 is an admirable number.

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (28), and also a Moran number because the ratio is a prime number: 761203 = 21313684 / (2 + 1 + 3 + 1 + 3 + 6 + 8 + 4).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 380574 + ... + 380629.

Almost surely, 2^21313684 is an apocalyptic number.

It is an amenable number.

21313684 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21313684 is a wasteful number, since it uses less digits than its factorization.

21313684 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 761214 (or 761212 counting only the distinct ones).

The product of its digits is 3456, while the sum is 28.

The square root of 21313684 is about 4616.6745607634. The cubic root of 21313684 is about 277.2593330414.

Adding to 21313684 its reverse (48631312), we get a palindrome (69944996).

The spelling of 21313684 in words is "twenty-one million, three hundred thirteen thousand, six hundred eighty-four".