644295983 has 2 divisors, whose sum is σ = 644295984. Its totient is φ = 644295982.

The previous prime is 644295959. The next prime is 644295991. The reversal of 644295983 is 389592446.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644295983 - 2⁸ = 644295727 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644295283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322147991 + 322147992.

It is an arithmetic number, because the mean of its divisors is an integer number (322147992).

Almost surely, 2^644295983 is an apocalyptic number.

644295983 is a deficient number, since it is larger than the sum of its proper divisors (1).

644295983 is an equidigital number, since it uses as much as digits as its factorization.

644295983 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1866240, while the sum is 50.

The square root of 644295983 is about 25382.9860930506. The cubic root of 644295983 is about 863.6977890913.

The spelling of 644295983 in words is "six hundred forty-four million, two hundred ninety-five thousand, nine hundred eighty-three".