644446141613 has 2 divisors, whose sum is σ = 644446141614. Its totient is φ = 644446141612.

The previous prime is 644446141531. The next prime is 644446141621. The reversal of 644446141613 is 316141644446.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 632308051684 + 12138089929 = 795178^2 + 110173^2 .

It is a cyclic number.

It is not a de Polignac number, because 644446141613 - 2⁸ = 644446141357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644446141013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322223070806 + 322223070807.

It is an arithmetic number, because the mean of its divisors is an integer number (322223070807).

Almost surely, 2^644446141613 is an apocalyptic number.

It is an amenable number.

644446141613 is a deficient number, since it is larger than the sum of its proper divisors (1).

644446141613 is an equidigital number, since it uses as much as digits as its factorization.

644446141613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 663552, while the sum is 44.

The spelling of 644446141613 in words is "six hundred forty-four billion, four hundred forty-six million, one hundred forty-one thousand, six hundred thirteen".