217368945 has 12 divisors (see below), whose sum is σ = 376772916. Its totient is φ = 115930080.

The previous prime is 217368941. The next prime is 217368967. The reversal of 217368945 is 549863712.

It can be written as a sum of positive squares in 2 ways, for example, as 88228449 + 129140496 = 9393^2 + 11364^2 .

It is not a de Polignac number, because 217368945 - 2² = 217368941 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 4830421 = 217368945 / (2 + 1 + 7 + 3 + 6 + 8 + 9 + 4 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 217368945.

It is not an unprimeable number, because it can be changed into a prime (217368941) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2415166 + ... + 2415255.

It is an arithmetic number, because the mean of its divisors is an integer number (31397743).

Almost surely, 2^217368945 is an apocalyptic number.

It is an amenable number.

217368945 is a deficient number, since it is larger than the sum of its proper divisors (159403971).

217368945 is a wasteful number, since it uses less digits than its factorization.

217368945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4830432 (or 4830429 counting only the distinct ones).

The product of its digits is 362880, while the sum is 45.

The square root of 217368945 is about 14743.4373536160. The cubic root of 217368945 is about 601.2648732855.

The spelling of 217368945 in words is "two hundred seventeen million, three hundred sixty-eight thousand, nine hundred forty-five".