641644477 has 2 divisors, whose sum is σ = 641644478. Its totient is φ = 641644476.

The previous prime is 641644453. The next prime is 641644571. The reversal of 641644477 is 774446146.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 395970201 + 245674276 = 19899^2 + 15674^2 .

It is a cyclic number.

It is not a de Polignac number, because 641644477 - 2⁷ = 641644349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (641641477) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320822238 + 320822239.

It is an arithmetic number, because the mean of its divisors is an integer number (320822239).

Almost surely, 2^641644477 is an apocalyptic number.

It is an amenable number.

641644477 is a deficient number, since it is larger than the sum of its proper divisors (1).

641644477 is an equidigital number, since it uses as much as digits as its factorization.

641644477 is an evil number, because the sum of its binary digits is even.

The product of its digits is 451584, while the sum is 43.

The square root of 641644477 is about 25330.7022603006. The cubic root of 641644477 is about 862.5113527036.

The spelling of 641644477 in words is "six hundred forty-one million, six hundred forty-four thousand, four hundred seventy-seven".