21710817 has 12 divisors (see below), whose sum is σ = 31417984. Its totient is φ = 14447160.

The previous prime is 21710813. The next prime is 21710833. The reversal of 21710817 is 71801712.

It is not a de Polignac number, because 21710817 - 2² = 21710813 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21710813) 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 11 ways as a sum of consecutive naturals, for example, 3768 + ... + 7590.

Almost surely, 2^21710817 is an apocalyptic number.

It is an amenable number.

21710817 is a deficient number, since it is larger than the sum of its proper divisors (9707167).

21710817 is a wasteful number, since it uses less digits than its factorization.

21710817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4460 (or 4457 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 27.

The square root of 21710817 is about 4659.4867743132. The cubic root of 21710817 is about 278.9707835441.

The spelling of 21710817 in words is "twenty-one million, seven hundred ten thousand, eight hundred seventeen".