21393715 has 32 divisors (see below), whose sum is σ = 31518720. Its totient is φ = 13613184.

The previous prime is 21393709. The next prime is 21393727. The reversal of 21393715 is 51739312.

It is a cyclic number.

It is not a de Polignac number, because 21393715 - 2³ = 21393707 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 34942 + ... + 35548.

It is an arithmetic number, because the mean of its divisors is an integer number (984960).

Almost surely, 2^21393715 is an apocalyptic number.

21393715 is a deficient number, since it is larger than the sum of its proper divisors (10125005).

21393715 is a wasteful number, since it uses less digits than its factorization.

21393715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 691.

The product of its digits is 5670, while the sum is 31.

The square root of 21393715 is about 4625.3340419909. The cubic root of 21393715 is about 277.6059276903.

The spelling of 21393715 in words is "twenty-one million, three hundred ninety-three thousand, seven hundred fifteen".