217790961 has 8 divisors (see below), whose sum is σ = 307469664. Its totient is φ = 136653120.

The previous prime is 217790959. The next prime is 217790987. The reversal of 217790961 is 169097712.

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 217790961 - 2¹ = 217790959 is a prime.

It is not an unprimeable number, because it can be changed into a prime (217790941) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2135155 + ... + 2135256.

It is an arithmetic number, because the mean of its divisors is an integer number (38433708).

Almost surely, 2^217790961 is an apocalyptic number.

It is an amenable number.

217790961 is a deficient number, since it is larger than the sum of its proper divisors (89678703).

217790961 is a wasteful number, since it uses less digits than its factorization.

217790961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4270431.

The product of its (nonzero) digits is 47628, while the sum is 42.

The square root of 217790961 is about 14757.7424086477. The cubic root of 217790961 is about 601.6537349690.

The spelling of 217790961 in words is "two hundred seventeen million, seven hundred ninety thousand, nine hundred sixty-one".