216206617257 has 20 divisors (see below), whose sum is σ = 323125035156. Its totient is φ = 144070928640.

The previous prime is 216206617241. The next prime is 216206617351. The reversal of 216206617257 is 752716602612.

216206617257 is a `hidden beast` number, since 2 + 1 + 6 + 2 + 0 + 6 + 617 + 25 + 7 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 146141056656 + 70065560601 = 382284^2 + 264699^2 .

It is not a de Polignac number, because 216206617257 - 2⁴ = 216206617241 is a prime.

It is not an unprimeable number, because it can be changed into a prime (216206657257) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 442548 + ... + 792629.

Almost surely, 2^216206617257 is an apocalyptic number.

216206617257 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

216206617257 is a deficient number, since it is larger than the sum of its proper divisors (106918417899).

216206617257 is a wasteful number, since it uses less digits than its factorization.

216206617257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1237350 (or 1237341 counting only the distinct ones).

The product of its (nonzero) digits is 423360, while the sum is 45.

The spelling of 216206617257 in words is "two hundred sixteen billion, two hundred six million, six hundred seventeen thousand, two hundred fifty-seven".