217285945 has 16 divisors (see below), whose sum is σ = 275535360. Its totient is φ = 164159424.

The previous prime is 217285933. The next prime is 217285961. The reversal of 217285945 is 549582712.

It is a cyclic number.

It is not a de Polignac number, because 217285945 - 2⁹ = 217285433 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2874 + ... + 21043.

It is an arithmetic number, because the mean of its divisors is an integer number (17220960).

Almost surely, 2^217285945 is an apocalyptic number.

It is an amenable number.

217285945 is a deficient number, since it is larger than the sum of its proper divisors (58249415).

217285945 is a wasteful number, since it uses less digits than its factorization.

217285945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24024.

The product of its digits is 201600, while the sum is 43.

The square root of 217285945 is about 14740.6222731607. The cubic root of 217285945 is about 601.1883346954.

The spelling of 217285945 in words is "two hundred seventeen million, two hundred eighty-five thousand, nine hundred forty-five".