665434658261 has 2 divisors, whose sum is σ = 665434658262. Its totient is φ = 665434658260.

The previous prime is 665434658243. The next prime is 665434658303. The reversal of 665434658261 is 162856434566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 439078516900 + 226356141361 = 662630^2 + 475769^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665434658261 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 665434658197 and 665434658206.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665434658201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332717329130 + 332717329131.

It is an arithmetic number, because the mean of its divisors is an integer number (332717329131).

Almost surely, 2^665434658261 is an apocalyptic number.

It is an amenable number.

665434658261 is a deficient number, since it is larger than the sum of its proper divisors (1).

665434658261 is an equidigital number, since it uses as much as digits as its factorization.

665434658261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24883200, while the sum is 56.

The spelling of 665434658261 in words is "six hundred sixty-five billion, four hundred thirty-four million, six hundred fifty-eight thousand, two hundred sixty-one".