217561264 has 20 divisors (see below), whose sum is σ = 422350200. Its totient is φ = 108567680.

The previous prime is 217561259. The next prime is 217561349. The reversal of 217561264 is 462165712.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4714 + ... + 21385.

It is an arithmetic number, because the mean of its divisors is an integer number (21117510).

Almost surely, 2^217561264 is an apocalyptic number.

It is an amenable number.

217561264 is a deficient number, since it is larger than the sum of its proper divisors (204788936).

217561264 is a wasteful number, since it uses less digits than its factorization.

217561264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26628 (or 26622 counting only the distinct ones).

The product of its digits is 20160, while the sum is 34.

The square root of 217561264 is about 14749.9581016354. The cubic root of 217561264 is about 601.4421457305.

The spelling of 217561264 in words is "two hundred seventeen million, five hundred sixty-one thousand, two hundred sixty-four".