671082685965661 has 2 divisors, whose sum is σ = 671082685965662. Its totient is φ = 671082685965660.

The previous prime is 671082685965641. The next prime is 671082685965673. The reversal of 671082685965661 is 166569586280176.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 562842695181636 + 108239990784025 = 23724306^2 + 10403845^2 .

It is a cyclic number.

It is not a de Polignac number, because 671082685965661 - 2⁴⁵ = 635898313876829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (671082685965611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335541342982830 + 335541342982831.

It is an arithmetic number, because the mean of its divisors is an integer number (335541342982831).

Almost surely, 2^{671082685965661} is an apocalyptic number.

It is an amenable number.

671082685965661 is a deficient number, since it is larger than the sum of its proper divisors (1).

671082685965661 is an equidigital number, since it uses as much as digits as its factorization.

671082685965661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1567641600, while the sum is 76.

The spelling of 671082685965661 in words is "six hundred seventy-one trillion, eighty-two billion, six hundred eighty-five million, nine hundred sixty-five thousand, six hundred sixty-one".