644877387293 has 2 divisors, whose sum is σ = 644877387294. Its totient is φ = 644877387292.

The previous prime is 644877387227. The next prime is 644877387307. The reversal of 644877387293 is 392783778446.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 637255748089 + 7621639204 = 798283^2 + 87302^2 .

It is a cyclic number.

It is not a de Polignac number, because 644877387293 - 2²⁴ = 644860610077 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644877387493) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322438693646 + 322438693647.

It is an arithmetic number, because the mean of its divisors is an integer number (322438693647).

Almost surely, 2^644877387293 is an apocalyptic number.

It is an amenable number.

644877387293 is a deficient number, since it is larger than the sum of its proper divisors (1).

644877387293 is an equidigital number, since it uses as much as digits as its factorization.

644877387293 is an evil number, because the sum of its binary digits is even.

The product of its digits is 341397504, while the sum is 68.

The spelling of 644877387293 in words is "six hundred forty-four billion, eight hundred seventy-seven million, three hundred eighty-seven thousand, two hundred ninety-three".