216986717 has 16 divisors (see below), whose sum is σ = 225756720. Its totient is φ = 208445952.

The previous prime is 216986711. The next prime is 216986743. The reversal of 216986717 is 717689612.

It can be written as a sum of positive squares in 8 ways, for example, as 2979076 + 214007641 = 1726^2 + 14629^2 .

It is a cyclic number.

It is not a de Polignac number, because 216986717 - 2²⁶ = 149877853 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 (216986711) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 740423 + ... + 740715.

It is an arithmetic number, because the mean of its divisors is an integer number (14109795).

Almost surely, 2^216986717 is an apocalyptic number.

It is an amenable number.

216986717 is a deficient number, since it is larger than the sum of its proper divisors (8770003).

216986717 is a wasteful number, since it uses less digits than its factorization.

216986717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 592.

The product of its digits is 254016, while the sum is 47.

The square root of 216986717 is about 14730.4690013591. The cubic root of 216986717 is about 600.9122391817.

The spelling of 216986717 in words is "two hundred sixteen million, nine hundred eighty-six thousand, seven hundred seventeen".