217983430656 has 78 divisors (see below), whose sum is σ = 629653145940. Its totient is φ = 72661131264.

The previous prime is 217983430591. The next prime is 217983430669. The reversal of 217983430656 is 656034389712.

217983430656 is a `hidden beast` number, since 2 + 1 + 79 + 83 + 430 + 65 + 6 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2919726 + ... + 2993453.

It is an arithmetic number, because the mean of its divisors is an integer number (8072476230).

It is a 1-persistent number, because it is pandigital, but 2⋅217983430656 = 435966861312 is not.

Almost surely, 2^217983430656 is an apocalyptic number.

It is an amenable number.

217983430656 is an abundant number, since it is smaller than the sum of its proper divisors (411669715284).

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

217983430656 is an equidigital number, since it uses as much as digits as its factorization.

217983430656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5913209 (or 5913184 counting only the distinct ones).

The product of its (nonzero) digits is 6531840, while the sum is 54.

The spelling of 217983430656 in words is "two hundred seventeen billion, nine hundred eighty-three million, four hundred thirty thousand, six hundred fifty-six".