217489784164 has 27 divisors (see below), whose sum is σ = 382541303641. Its totient is φ = 108195056000.

The previous prime is 217489784137. The next prime is 217489784177. The reversal of 217489784164 is 461487984712.

It is a happy number.

The square root of 217489784164 is 466358.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 4193598564 + 213296185600 = 64758^2 + 461840^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 234111252 + ... + 234112180.

Almost surely, 2^217489784164 is an apocalyptic number.

217489784164 is the 466358-th square number.

It is an amenable number.

217489784164 is a deficient number, since it is larger than the sum of its proper divisors (165051519477).

217489784164 is an frugal number, since it uses more digits than its factorization.

217489784164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2364 (or 1182 counting only the distinct ones).

The product of its digits is 21676032, while the sum is 61.

The spelling of 217489784164 in words is "two hundred seventeen billion, four hundred eighty-nine million, seven hundred eighty-four thousand, one hundred sixty-four".