561665311 has 2 divisors, whose sum is σ = 561665312. Its totient is φ = 561665310.

The previous prime is 561665303. The next prime is 561665333. The reversal of 561665311 is 113566165.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 561665311 - 2³ = 561665303 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (561665371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 280832655 + 280832656.

It is an arithmetic number, because the mean of its divisors is an integer number (280832656).

Almost surely, 2^561665311 is an apocalyptic number.

561665311 is a deficient number, since it is larger than the sum of its proper divisors (1).

561665311 is an equidigital number, since it uses as much as digits as its factorization.

561665311 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16200, while the sum is 34.

The square root of 561665311 is about 23699.4791292973. The cubic root of 561665311 is about 825.0733015983.

The spelling of 561665311 in words is "five hundred sixty-one million, six hundred sixty-five thousand, three hundred eleven".