643635340 has 12 divisors (see below), whose sum is σ = 1351634256. Its totient is φ = 257454128.

The previous prime is 643635331. The next prime is 643635341. The reversal of 643635340 is 43536346.

It is a junction number, because it is equal to n+sod(n) for n = 643635296 and 643635305.

It is not an unprimeable number, because it can be changed into a prime (643635341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16090864 + ... + 16090903.

It is an arithmetic number, because the mean of its divisors is an integer number (112636188).

Almost surely, 2^643635340 is an apocalyptic number.

It is an amenable number.

643635340 is an abundant number, since it is smaller than the sum of its proper divisors (707998916).

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

643635340 is a wasteful number, since it uses less digits than its factorization.

643635340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32181776 (or 32181774 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 34.

The square root of 643635340 is about 25369.9692550070. The cubic root of 643635340 is about 863.4024843199.

The spelling of 643635340 in words is "six hundred forty-three million, six hundred thirty-five thousand, three hundred forty".