21702717 has 6 divisors (see below), whose sum is σ = 31348382. Its totient is φ = 14468472.

The previous prime is 21702679. The next prime is 21702719. The reversal of 21702717 is 71720712.

It can be written as a sum of positive squares in only one way, i.e., 18096516 + 3606201 = 4254^2 + 1899^2 .

It is not a de Polignac number, because 21702717 - 2¹¹ = 21700669 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21702719) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1205698 + ... + 1205715.

Almost surely, 2^21702717 is an apocalyptic number.

It is an amenable number.

21702717 is a deficient number, since it is larger than the sum of its proper divisors (9645665).

21702717 is a wasteful number, since it uses less digits than its factorization.

21702717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2411419 (or 2411416 counting only the distinct ones).

The product of its (nonzero) digits is 1372, while the sum is 27.

The square root of 21702717 is about 4658.6174987865. The cubic root of 21702717 is about 278.9360858721.

The spelling of 21702717 in words is "twenty-one million, seven hundred two thousand, seven hundred seventeen".