21310715 has 4 divisors (see below), whose sum is σ = 25572864. Its totient is φ = 17048568.

The previous prime is 21310669. The next prime is 21310739. The reversal of 21310715 is 51701312.

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 21310715 - 2⁶ = 21310651 is a prime.

It is a super-2 number, since 2×21310715² = 908293147622450, which contains 22 as substring.

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, 2131067 + ... + 2131076.

It is an arithmetic number, because the mean of its divisors is an integer number (6393216).

Almost surely, 2^21310715 is an apocalyptic number.

21310715 is a deficient number, since it is larger than the sum of its proper divisors (4262149).

21310715 is an equidigital number, since it uses as much as digits as its factorization.

21310715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4262148.

The product of its (nonzero) digits is 210, while the sum is 20.

The square root of 21310715 is about 4616.3529977678. The cubic root of 21310715 is about 277.2464583520.

The spelling of 21310715 in words is "twenty-one million, three hundred ten thousand, seven hundred fifteen".