643335264 has 384 divisors, whose sum is σ = 2275983360. Its totient is φ = 174182400.

The previous prime is 643335263. The next prime is 643335271. The reversal of 643335264 is 462533346.

643335264 is a `hidden beast` number, since 64 + 3 + 335 + 264 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643335263) 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, 5065569 + ... + 5065695.

It is an arithmetic number, because the mean of its divisors is an integer number (5927040).

Almost surely, 2^643335264 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 643335264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1137991680).

643335264 is an abundant number, since it is smaller than the sum of its proper divisors (1632648096).

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

643335264 is a wasteful number, since it uses less digits than its factorization.

643335264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211 (or 197 counting only the distinct ones).

The product of its digits is 155520, while the sum is 36.

The square root of 643335264 is about 25364.0545654672. The cubic root of 643335264 is about 863.2682848118.

The spelling of 643335264 in words is "six hundred forty-three million, three hundred thirty-five thousand, two hundred sixty-four".