644373674 has 16 divisors (see below), whose sum is σ = 1104969600. Its totient is φ = 276077904.

The previous prime is 644373647. The next prime is 644373679. The reversal of 644373674 is 476373446.

It is a happy number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (644373679) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 78392 + ... + 86220.

It is an arithmetic number, because the mean of its divisors is an integer number (69060600).

Almost surely, 2^644373674 is an apocalyptic number.

644373674 is a deficient number, since it is larger than the sum of its proper divisors (460595926).

644373674 is a wasteful number, since it uses less digits than its factorization.

644373674 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13717.

The product of its digits is 1016064, while the sum is 44.

The square root of 644373674 is about 25384.5164224178. The cubic root of 644373674 is about 863.7325033892.

The spelling of 644373674 in words is "six hundred forty-four million, three hundred seventy-three thousand, six hundred seventy-four".