217568945 has 8 divisors (see below), whose sum is σ = 284817600. Its totient is φ = 158231920.

The previous prime is 217568929. The next prime is 217568959. The reversal of 217568945 is 549865712.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 217568945 - 2⁴ = 217568929 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 217568945.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1977845 + ... + 1977954.

It is an arithmetic number, because the mean of its divisors is an integer number (35602200).

Almost surely, 2^217568945 is an apocalyptic number.

It is an amenable number.

217568945 is a deficient number, since it is larger than the sum of its proper divisors (67248655).

217568945 is a wasteful number, since it uses less digits than its factorization.

217568945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3955815.

The product of its digits is 604800, while the sum is 47.

The square root of 217568945 is about 14750.2184729583. The cubic root of 217568945 is about 601.4492236184.

The spelling of 217568945 in words is "two hundred seventeen million, five hundred sixty-eight thousand, nine hundred forty-five".