643830 has 32 divisors (see below), whose sum is σ = 1686528. Its totient is φ = 156000.

The previous prime is 643781. The next prime is 643847. The reversal of 643830 is 38346.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 643830.

It is a congruent number.

It is an unprimeable number.

643830 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 646 + ... + 1305.

It is an arithmetic number, because the mean of its divisors is an integer number (52704).

2⁶⁴³⁸³⁰ is an apocalyptic number.

643830 is an abundant number, since it is smaller than the sum of its proper divisors (1042698).

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

643830 is a wasteful number, since it uses less digits than its factorization.

643830 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1972.

The product of its (nonzero) digits is 1728, while the sum is 24.

The square root of 643830 is about 802.3901794015. The cubic root of 643830 is about 86.3489517549.

The spelling of 643830 in words is "six hundred forty-three thousand, eight hundred thirty".