216817816656 has 80 divisors (see below), whose sum is σ = 646466802048. Its totient is φ = 61334592000.

The previous prime is 216817816643. The next prime is 216817816669. The reversal of 216817816656 is 656618718612.

It is an interprime number because it is at equal distance from previous prime (216817816643) and next prime (216817816669).

It is a junction number, because it is equal to n+sod(n) for n = 216817816596 and 216817816605.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3160575 + ... + 3228446.

Almost surely, 2^216817816656 is an apocalyptic number.

It is an amenable number.

216817816656 is an abundant number, since it is smaller than the sum of its proper divisors (429648985392).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

216817816656 is a wasteful number, since it uses less digits than its factorization.

216817816656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6389140 (or 6389134 counting only the distinct ones).

The product of its digits is 5806080, while the sum is 57.

The spelling of 216817816656 in words is "two hundred sixteen billion, eight hundred seventeen million, eight hundred sixteen thousand, six hundred fifty-six".