217185960961 has 4 divisors (see below), whose sum is σ = 217188037332. Its totient is φ = 217183884592.

The previous prime is 217185960923. The next prime is 217185960973. The reversal of 217185960961 is 169069581712.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 192172640625 + 25013320336 = 438375^2 + 158156^2 .

It is a cyclic number.

It is not a de Polignac number, because 217185960961 - 2⁹ = 217185960449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217185960161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 872470 + ... + 1093423.

It is an arithmetic number, because the mean of its divisors is an integer number (54297009333).

Almost surely, 2^217185960961 is an apocalyptic number.

It is an amenable number.

217185960961 is a deficient number, since it is larger than the sum of its proper divisors (2076371).

217185960961 is a wasteful number, since it uses less digits than its factorization.

217185960961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2076370.

The product of its (nonzero) digits is 1632960, while the sum is 55.

The spelling of 217185960961 in words is "two hundred seventeen billion, one hundred eighty-five million, nine hundred sixty thousand, nine hundred sixty-one".