644706383 has 2 divisors, whose sum is σ = 644706384. Its totient is φ = 644706382.

The previous prime is 644706373. The next prime is 644706397. The reversal of 644706383 is 383607446.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 644706383 - 2⁴ = 644706367 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 644706383.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644706313) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322353191 + 322353192.

It is an arithmetic number, because the mean of its divisors is an integer number (322353192).

Almost surely, 2^644706383 is an apocalyptic number.

644706383 is a deficient number, since it is larger than the sum of its proper divisors (1).

644706383 is an equidigital number, since it uses as much as digits as its factorization.

644706383 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 290304, while the sum is 41.

The square root of 644706383 is about 25391.0689613494. The cubic root of 644706383 is about 863.8811346073.

The spelling of 644706383 in words is "six hundred forty-four million, seven hundred six thousand, three hundred eighty-three".