217018961 has 4 divisors (see below), whose sum is σ = 226454592. Its totient is φ = 207583332.

The previous prime is 217018939. The next prime is 217018987. The reversal of 217018961 is 169810712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-217018961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217011961) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4717781 + ... + 4717826.

It is an arithmetic number, because the mean of its divisors is an integer number (56613648).

Almost surely, 2^217018961 is an apocalyptic number.

It is an amenable number.

217018961 is a deficient number, since it is larger than the sum of its proper divisors (9435631).

217018961 is an equidigital number, since it uses as much as digits as its factorization.

217018961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9435630.

The product of its (nonzero) digits is 6048, while the sum is 35.

The square root of 217018961 is about 14731.5634268736. The cubic root of 217018961 is about 600.9420026850.

The spelling of 217018961 in words is "two hundred seventeen million, eighteen thousand, nine hundred sixty-one".