21913713 has 8 divisors (see below), whose sum is σ = 32464800. Its totient is φ = 14609124.

The previous prime is 21913711. The next prime is 21913729. The reversal of 21913713 is 31731912.

It is not a de Polignac number, because 21913713 - 2¹ = 21913711 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 811619 = 21913713 / (2 + 1 + 9 + 1 + 3 + 7 + 1 + 3).

It is not an unprimeable number, because it can be changed into a prime (21913711) by changing a digit.

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, 405783 + ... + 405836.

It is an arithmetic number, because the mean of its divisors is an integer number (4058100).

Almost surely, 2^21913713 is an apocalyptic number.

It is an amenable number.

21913713 is a deficient number, since it is larger than the sum of its proper divisors (10551087).

21913713 is an equidigital number, since it uses as much as digits as its factorization.

21913713 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 811628 (or 811622 counting only the distinct ones).

The product of its digits is 1134, while the sum is 27.

The square root of 21913713 is about 4681.2084978134. The cubic root of 21913713 is about 279.8371204053.

The spelling of 21913713 in words is "twenty-one million, nine hundred thirteen thousand, seven hundred thirteen".