643000 has 32 divisors (see below), whose sum is σ = 1506960. Its totient is φ = 256800.

The previous prime is 642997. The next prime is 643009. The reversal of 643000 is 346.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643009) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 679 + ... + 1321.

2⁶⁴³⁰⁰⁰ 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 643000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (753480).

643000 is an abundant number, since it is smaller than the sum of its proper divisors (863960).

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

643000 is a wasteful number, since it uses less digits than its factorization.

643000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 664 (or 650 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 643000 is about 801.8728078692. The cubic root of 643000 is about 86.3118299216.

Adding to 643000 its reverse (346), we get a palindrome (643346).

The spelling of 643000 in words is "six hundred forty-three thousand".