644777622 has 24 divisors (see below), whose sum is σ = 1407220776. Its totient is φ = 213356256.

The previous prime is 644777621. The next prime is 644777641. The reversal of 644777622 is 226777446.

644777622 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644777621) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 128268 + ... + 133199.

It is an arithmetic number, because the mean of its divisors is an integer number (58634199).

Almost surely, 2^644777622 is an apocalyptic number.

644777622 is an abundant number, since it is smaller than the sum of its proper divisors (762443154).

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

644777622 is a wasteful number, since it uses less digits than its factorization.

644777622 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261612 (or 261609 counting only the distinct ones).

The product of its digits is 790272, while the sum is 45.

The square root of 644777622 is about 25392.4717583775. The cubic root of 644777622 is about 863.9129525858.

The spelling of 644777622 in words is "six hundred forty-four million, seven hundred seventy-seven thousand, six hundred twenty-two".