644387702 has 16 divisors (see below), whose sum is σ = 1105158912. Its totient is φ = 276042600.

The previous prime is 644387701. The next prime is 644387741. The reversal of 644387702 is 207783446.

644387702 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 644387702.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644387701) 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, 26693 + ... + 44735.

It is an arithmetic number, because the mean of its divisors is an integer number (69072432).

Almost surely, 2^644387702 is an apocalyptic number.

644387702 is a deficient number, since it is larger than the sum of its proper divisors (460771210).

644387702 is a wasteful number, since it uses less digits than its factorization.

644387702 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20603.

The product of its (nonzero) digits is 225792, while the sum is 41.

The square root of 644387702 is about 25384.7927310821. The cubic root of 644387702 is about 863.7387711559.

The spelling of 644387702 in words is "six hundred forty-four million, three hundred eighty-seven thousand, seven hundred two".