643673000 has 64 divisors (see below), whose sum is σ = 1521346320. Its totient is φ = 254880000.

The previous prime is 643672907. The next prime is 643673011. The reversal of 643673000 is 376346.

It can be written as a sum of positive squares in 8 ways, for example, as 236359876 + 407313124 = 15374^2 + 20182^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 97814 + ... + 104186.

Almost surely, 2^643673000 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 643673000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (760673160).

643673000 is an abundant number, since it is smaller than the sum of its proper divisors (877673320).

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

643673000 is a wasteful number, since it uses less digits than its factorization.

643673000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6495 (or 6481 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 29.

The square root of 643673000 is about 25370.7114602646. The cubic root of 643673000 is about 863.4193236187.

The spelling of 643673000 in words is "six hundred forty-three million, six hundred seventy-three thousand".