643591872 has 336 divisors, whose sum is σ = 2404506240. Its totient is φ = 166924800.

The previous prime is 643591859. The next prime is 643591873. The reversal of 643591872 is 278195346.

It is a tau number, because it is divible by the number of its divisors (336).

It is not an unprimeable number, because it can be changed into a prime (643591873) 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, 931047 + ... + 931737.

Almost surely, 2^643591872 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 643591872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1202253120).

643591872 is an abundant number, since it is smaller than the sum of its proper divisors (1760914368).

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

643591872 is a wasteful number, since it uses less digits than its factorization.

643591872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 737 (or 714 counting only the distinct ones).

The product of its digits is 362880, while the sum is 45.

The square root of 643591872 is about 25369.1125583849. The cubic root of 643591872 is about 863.3830472143.

The spelling of 643591872 in words is "six hundred forty-three million, five hundred ninety-one thousand, eight hundred seventy-two".