217816664 has 48 divisors (see below), whose sum is σ = 456592320. Its totient is φ = 97269120.

The previous prime is 217816661. The next prime is 217816673. The reversal of 217816664 is 466618712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217816661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 39314 + ... + 44510.

It is an arithmetic number, because the mean of its divisors is an integer number (9512340).

Almost surely, 2^217816664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 217816664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (228296160).

217816664 is an abundant number, since it is smaller than the sum of its proper divisors (238775656).

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

217816664 is a wasteful number, since it uses less digits than its factorization.

217816664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5260 (or 5243 counting only the distinct ones).

The product of its digits is 96768, while the sum is 41.

The square root of 217816664 is about 14758.6132139846. The cubic root of 217816664 is about 601.6774024612.

The spelling of 217816664 in words is "two hundred seventeen million, eight hundred sixteen thousand, six hundred sixty-four".