216756217 has 8 divisors (see below), whose sum is σ = 222251400. Its totient is φ = 211271040.

The previous prime is 216756203. The next prime is 216756229. The reversal of 216756217 is 712657612.

It can be written as a sum of positive squares in 4 ways, for example, as 19044496 + 197711721 = 4364^2 + 14061^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216756217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216756257) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 61803 + ... + 65215.

It is an arithmetic number, because the mean of its divisors is an integer number (27781425).

Almost surely, 2^216756217 is an apocalyptic number.

It is an amenable number.

216756217 is a deficient number, since it is larger than the sum of its proper divisors (5495183).

216756217 is a wasteful number, since it uses less digits than its factorization.

216756217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5003.

The product of its digits is 35280, while the sum is 37.

The square root of 216756217 is about 14722.6430032111. The cubic root of 216756217 is about 600.6993853760.

The spelling of 216756217 in words is "two hundred sixteen million, seven hundred fifty-six thousand, two hundred seventeen".