644271380 has 48 divisors (see below), whose sum is σ = 1462702080. Its totient is φ = 237541248.

The previous prime is 644271371. The next prime is 644271401. The reversal of 644271380 is 83172446.

It is a super-3 number, since 3×644271380³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 644271380.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8852 + ... + 36971.

It is an arithmetic number, because the mean of its divisors is an integer number (30472960).

Almost surely, 2^644271380 is an apocalyptic number.

It is an amenable number.

644271380 is an abundant number, since it is smaller than the sum of its proper divisors (818430700).

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

644271380 is a wasteful number, since it uses less digits than its factorization.

644271380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45888 (or 45886 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 35.

The square root of 644271380 is about 25382.5014527725. The cubic root of 644271380 is about 863.6867952687.

The spelling of 644271380 in words is "six hundred forty-four million, two hundred seventy-one thousand, three hundred eighty".