644802270 has 128 divisors (see below), whose sum is σ = 1819238400. Its totient is φ = 146200320.

The previous prime is 644802251. The next prime is 644802283. The reversal of 644802270 is 72208446.

644802270 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2294530 + ... + 2294810.

It is an arithmetic number, because the mean of its divisors is an integer number (14212800).

Almost surely, 2^644802270 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644802270, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (909619200).

644802270 is an abundant number, since it is smaller than the sum of its proper divisors (1174436130).

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

644802270 is a wasteful number, since it uses less digits than its factorization.

644802270 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 535 (or 521 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 33.

The square root of 644802270 is about 25392.9570944386. The cubic root of 644802270 is about 863.9239607507.

The spelling of 644802270 in words is "six hundred forty-four million, eight hundred two thousand, two hundred seventy".