217649268 has 36 divisors (see below), whose sum is σ = 570548160. Its totient is φ = 72549432.

The previous prime is 217649251. The next prime is 217649291. The reversal of 217649268 is 862946712.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 110988 + ... + 112931.

It is an arithmetic number, because the mean of its divisors is an integer number (15848560).

Almost surely, 2^217649268 is an apocalyptic number.

It is an amenable number.

217649268 is an abundant number, since it is smaller than the sum of its proper divisors (352898892).

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

217649268 is a wasteful number, since it uses less digits than its factorization.

217649268 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223938 (or 223924 counting only the distinct ones).

The product of its digits is 290304, while the sum is 45.

The square root of 217649268 is about 14752.9409949339. The cubic root of 217649268 is about 601.5232296798.

The spelling of 217649268 in words is "two hundred seventeen million, six hundred forty-nine thousand, two hundred sixty-eight".