21715713 has 6 divisors (see below), whose sum is σ = 31367154. Its totient is φ = 14477136.

The previous prime is 21715711. The next prime is 21715721. The reversal of 21715713 is 31751712.

It is a happy number.

21715713 is a `hidden beast` number, since 21 + 71 + 571 + 3 = 666.

It can be written as a sum of positive squares in only one way, i.e., 21594609 + 121104 = 4647^2 + 348^2 .

It is not a de Polignac number, because 21715713 - 2¹ = 21715711 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21715711) 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 5 ways as a sum of consecutive naturals, for example, 1206420 + ... + 1206437.

It is an arithmetic number, because the mean of its divisors is an integer number (5227859).

Almost surely, 2^21715713 is an apocalyptic number.

It is an amenable number.

21715713 is a deficient number, since it is larger than the sum of its proper divisors (9651441).

21715713 is a wasteful number, since it uses less digits than its factorization.

21715713 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2412863 (or 2412860 counting only the distinct ones).

The product of its digits is 1470, while the sum is 27.

The square root of 21715713 is about 4660.0121244477. The cubic root of 21715713 is about 278.9917521746.

The spelling of 21715713 in words is "twenty-one million, seven hundred fifteen thousand, seven hundred thirteen".