561665171 has 2 divisors, whose sum is σ = 561665172. Its totient is φ = 561665170.

The previous prime is 561665131. The next prime is 561665177. The reversal of 561665171 is 171566165.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 561665171 - 2¹⁸ = 561403027 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (561665177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 280832585 + 280832586.

It is an arithmetic number, because the mean of its divisors is an integer number (280832586).

Almost surely, 2^561665171 is an apocalyptic number.

561665171 is a deficient number, since it is larger than the sum of its proper divisors (1).

561665171 is an equidigital number, since it uses as much as digits as its factorization.

561665171 is an evil number, because the sum of its binary digits is even.

The product of its digits is 37800, while the sum is 38.

The square root of 561665171 is about 23699.4761756457. The cubic root of 561665171 is about 825.0732330461.

The spelling of 561665171 in words is "five hundred sixty-one million, six hundred sixty-five thousand, one hundred seventy-one".