644810316697 has 2 divisors, whose sum is σ = 644810316698. Its totient is φ = 644810316696.

The previous prime is 644810316643. The next prime is 644810316719. The reversal of 644810316697 is 796613018446.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 439278653961 + 205531662736 = 662781^2 + 453356^2 .

It is a cyclic number.

It is not a de Polignac number, because 644810316697 - 2³⁵ = 610450578329 is a prime.

It is not a weakly prime, because it can be changed into another prime (644810316797) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322405158348 + 322405158349.

It is an arithmetic number, because the mean of its divisors is an integer number (322405158349).

Almost surely, 2^644810316697 is an apocalyptic number.

It is an amenable number.

644810316697 is a deficient number, since it is larger than the sum of its proper divisors (1).

644810316697 is an equidigital number, since it uses as much as digits as its factorization.

644810316697 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5225472, while the sum is 55.

The spelling of 644810316697 in words is "six hundred forty-four billion, eight hundred ten million, three hundred sixteen thousand, six hundred ninety-seven".