667644941 has 2 divisors, whose sum is σ = 667644942. Its totient is φ = 667644940.

The previous prime is 667644937. The next prime is 667644953. The reversal of 667644941 is 149446766.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 658127716 + 9517225 = 25654^2 + 3085^2 .

It is a cyclic number.

It is not a de Polignac number, because 667644941 - 2² = 667644937 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (667644911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333822470 + 333822471.

It is an arithmetic number, because the mean of its divisors is an integer number (333822471).

Almost surely, 2^667644941 is an apocalyptic number.

It is an amenable number.

667644941 is a deficient number, since it is larger than the sum of its proper divisors (1).

667644941 is an equidigital number, since it uses as much as digits as its factorization.

667644941 is an evil number, because the sum of its binary digits is even.

The product of its digits is 870912, while the sum is 47.

The square root of 667644941 is about 25838.8262310810. The cubic root of 667644941 is about 874.0075565713.

The spelling of 667644941 in words is "six hundred sixty-seven million, six hundred forty-four thousand, nine hundred forty-one".