21715365 has 16 divisors (see below), whose sum is σ = 39708288. Its totient is φ = 9926976.

The previous prime is 21715361. The next prime is 21715433. The reversal of 21715365 is 56351712.

It is not a de Polignac number, because 21715365 - 2² = 21715361 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21715361) 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 15 ways as a sum of consecutive naturals, for example, 103302 + ... + 103511.

It is an arithmetic number, because the mean of its divisors is an integer number (2481768).

Almost surely, 2^21715365 is an apocalyptic number.

It is an amenable number.

21715365 is a deficient number, since it is larger than the sum of its proper divisors (17992923).

21715365 is a wasteful number, since it uses less digits than its factorization.

21715365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206828.

The product of its digits is 6300, while the sum is 30.

The square root of 21715365 is about 4659.9747853395. The cubic root of 21715365 is about 278.9902618613.

The spelling of 21715365 in words is "twenty-one million, seven hundred fifteen thousand, three hundred sixty-five".