644033432 has 64 divisors (see below), whose sum is σ = 1430016000. Its totient is φ = 266094720.

The previous prime is 644033393. The next prime is 644033447. The reversal of 644033432 is 234330446.

It is a junction number, because it is equal to n+sod(n) for n = 644033395 and 644033404.

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, 605333 + ... + 606395.

It is an arithmetic number, because the mean of its divisors is an integer number (22344000).

Almost surely, 2^644033432 is an apocalyptic number.

644033432 is a gapful number since it is divisible by the number (62) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644033432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (715008000).

644033432 is an abundant number, since it is smaller than the sum of its proper divisors (785982568).

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

644033432 is a wasteful number, since it uses less digits than its factorization.

644033432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1456 (or 1452 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 29.

The square root of 644033432 is about 25377.8137750280. The cubic root of 644033432 is about 863.5804540293.

Adding to 644033432 its reverse (234330446), we get a palindrome (878363878).

The spelling of 644033432 in words is "six hundred forty-four million, thirty-three thousand, four hundred thirty-two".