671316661 has 2 divisors, whose sum is σ = 671316662. Its totient is φ = 671316660.

The previous prime is 671316643. The next prime is 671316673. The reversal of 671316661 is 166613176.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 567154225 + 104162436 = 23815^2 + 10206^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-671316661 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 671316661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (671316601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335658330 + 335658331.

It is an arithmetic number, because the mean of its divisors is an integer number (335658331).

Almost surely, 2^671316661 is an apocalyptic number.

It is an amenable number.

671316661 is a deficient number, since it is larger than the sum of its proper divisors (1).

671316661 is an equidigital number, since it uses as much as digits as its factorization.

671316661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27216, while the sum is 37.

The square root of 671316661 is about 25909.7792541735. The cubic root of 671316661 is about 875.6068328188.

The spelling of 671316661 in words is "six hundred seventy-one million, three hundred sixteen thousand, six hundred sixty-one".