216643564506 has 32 divisors (see below), whose sum is σ = 438236870400. Its totient is φ = 71389866240.

The previous prime is 216643564481. The next prime is 216643564537. The reversal of 216643564506 is 605465346612.

It is a Curzon 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, 3083286 + ... + 3152766.

It is an arithmetic number, because the mean of its divisors is an integer number (13694902200).

Almost surely, 2^216643564506 is an apocalyptic number.

216643564506 is an abundant number, since it is smaller than the sum of its proper divisors (221593305894).

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

216643564506 is a wasteful number, since it uses less digits than its factorization.

216643564506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75414.

The product of its (nonzero) digits is 3110400, while the sum is 48.

The spelling of 216643564506 in words is "two hundred sixteen billion, six hundred forty-three million, five hundred sixty-four thousand, five hundred six".