644143800 has 48 divisors (see below), whose sum is σ = 1996847640. Its totient is φ = 171771520.

The previous prime is 644143793. The next prime is 644143813. The reversal of 644143800 is 8341446.

644143800 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 536187 + ... + 537386.

Almost surely, 2^644143800 is an apocalyptic number.

644143800 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

644143800 is an abundant number, since it is smaller than the sum of its proper divisors (1352703840).

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

644143800 is a wasteful number, since it uses less digits than its factorization.

644143800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1073592 (or 1073583 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 30.

The square root of 644143800 is about 25379.9881796663. The cubic root of 644143800 is about 863.6297818016.

The spelling of 644143800 in words is "six hundred forty-four million, one hundred forty-three thousand, eight hundred".