644746042 has 16 divisors (see below), whose sum is σ = 990380160. Its totient is φ = 314631072.

The previous prime is 644745971. The next prime is 644746049. The reversal of 644746042 is 240647446.

644746042 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 644745992 and 644746010.

It is not an unprimeable number, because it can be changed into a prime (644746049) 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, 162559 + ... + 166477.

It is an arithmetic number, because the mean of its divisors is an integer number (61898760).

Almost surely, 2^644746042 is an apocalyptic number.

644746042 is a deficient number, since it is larger than the sum of its proper divisors (345634118).

644746042 is a wasteful number, since it uses less digits than its factorization.

644746042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5877.

The product of its (nonzero) digits is 129024, while the sum is 37.

The square root of 644746042 is about 25391.8499129150. The cubic root of 644746042 is about 863.8988480762.

The spelling of 644746042 in words is "six hundred forty-four million, seven hundred forty-six thousand, forty-two".