643635330 has 128 divisors (see below), whose sum is σ = 1734082560. Its totient is φ = 151822080.

The previous prime is 643635323. The next prime is 643635331. The reversal of 643635330 is 33536346.

It is a junction number, because it is equal to n+sod(n) for n = 643635291 and 643635300.

It is not an unprimeable number, because it can be changed into a prime (643635331) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1680319 + ... + 1680701.

It is an arithmetic number, because the mean of its divisors is an integer number (13547520).

Almost surely, 2^643635330 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643635330, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (867041280).

643635330 is an abundant number, since it is smaller than the sum of its proper divisors (1090447230).

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

643635330 is a wasteful number, since it uses less digits than its factorization.

643635330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 576.

The product of its (nonzero) digits is 58320, while the sum is 33.

The square root of 643635330 is about 25369.9690579236. The cubic root of 643635330 is about 863.4024798484.

The spelling of 643635330 in words is "six hundred forty-three million, six hundred thirty-five thousand, three hundred thirty".