21647313 has 12 divisors (see below), whose sum is σ = 31646160. Its totient is φ = 14257176.

The previous prime is 21647299. The next prime is 21647321. The reversal of 21647313 is 31374612.

21647313 is a `hidden beast` number, since 2 + 1 + 647 + 3 + 13 = 666.

It is not a de Polignac number, because 21647313 - 2⁵ = 21647281 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21647323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13743 + ... + 15236.

It is an arithmetic number, because the mean of its divisors is an integer number (2637180).

Almost surely, 2^21647313 is an apocalyptic number.

It is an amenable number.

21647313 is a deficient number, since it is larger than the sum of its proper divisors (9998847).

21647313 is a wasteful number, since it uses less digits than its factorization.

21647313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29068 (or 29065 counting only the distinct ones).

The product of its digits is 3024, while the sum is 27.

The square root of 21647313 is about 4652.6672995176. The cubic root of 21647313 is about 278.6985220014.

The spelling of 21647313 in words is "twenty-one million, six hundred forty-seven thousand, three hundred thirteen".