643903344 has 240 divisors, whose sum is σ = 2177360640. Its totient is φ = 180403200.

The previous prime is 643903343. The next prime is 643903361. The reversal of 643903344 is 443309346.

It is a happy number.

643903344 is a `hidden beast` number, since 643 + 9 + 0 + 3 + 3 + 4 + 4 = 666.

It is a super-2 number, since 2×643903344² = 829223032828764672, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 643903299 and 643903308.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643903343) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1605544 + ... + 1605944.

It is an arithmetic number, because the mean of its divisors is an integer number (9072336).

Almost surely, 2^643903344 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643903344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1088680320).

643903344 is an abundant number, since it is smaller than the sum of its proper divisors (1533457296).

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

643903344 is a wasteful number, since it uses less digits than its factorization.

643903344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 490 (or 472 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 36.

The square root of 643903344 is about 25375.2506194520. The cubic root of 643903344 is about 863.5223053818.

The spelling of 643903344 in words is "six hundred forty-three million, nine hundred three thousand, three hundred forty-four".