644719746 has 32 divisors (see below), whose sum is σ = 1444684608. Its totient is φ = 190088640.

The previous prime is 644719703. The next prime is 644719759. The reversal of 644719746 is 647917446.

It is a junction number, because it is equal to n+sod(n) for n = 644719695 and 644719704.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 129565 + ... + 134448.

It is an arithmetic number, because the mean of its divisors is an integer number (45146394).

Almost surely, 2^644719746 is an apocalyptic number.

644719746 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

644719746 is an abundant number, since it is smaller than the sum of its proper divisors (799964862).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644719746 is a wasteful number, since it uses less digits than its factorization.

644719746 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 264066.

The product of its digits is 1016064, while the sum is 48.

The square root of 644719746 is about 25391.3321036924. The cubic root of 644719746 is about 863.8871031971.

The spelling of 644719746 in words is "six hundred forty-four million, seven hundred nineteen thousand, seven hundred forty-six".