665635167121 has 2 divisors, whose sum is σ = 665635167122. Its totient is φ = 665635167120.

The previous prime is 665635167103. The next prime is 665635167163. The reversal of 665635167121 is 121761536566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 586547666496 + 79087500625 = 765864^2 + 281225^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665635167121 is a prime.

It is not a weakly prime, because it can be changed into another prime (665635167721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332817583560 + 332817583561.

It is an arithmetic number, because the mean of its divisors is an integer number (332817583561).

Almost surely, 2^665635167121 is an apocalyptic number.

It is an amenable number.

665635167121 is a deficient number, since it is larger than the sum of its proper divisors (1).

665635167121 is an equidigital number, since it uses as much as digits as its factorization.

665635167121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1360800, while the sum is 49.

The spelling of 665635167121 in words is "six hundred sixty-five billion, six hundred thirty-five million, one hundred sixty-seven thousand, one hundred twenty-one".