21313715 has 4 divisors (see below), whose sum is σ = 25576464. Its totient is φ = 17050968.

The previous prime is 21313697. The next prime is 21313729. The reversal of 21313715 is 51731312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21313715 - 2²² = 17119411 is a prime.

It is a Duffinian 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, 2131367 + ... + 2131376.

It is an arithmetic number, because the mean of its divisors is an integer number (6394116).

Almost surely, 2^21313715 is an apocalyptic number.

21313715 is a deficient number, since it is larger than the sum of its proper divisors (4262749).

21313715 is an equidigital number, since it uses as much as digits as its factorization.

21313715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4262748.

The product of its digits is 630, while the sum is 23.

The square root of 21313715 is about 4616.6779181572. The cubic root of 21313715 is about 277.2594674626.

The spelling of 21313715 in words is "twenty-one million, three hundred thirteen thousand, seven hundred fifteen".