643770 has 48 divisors (see below), whose sum is σ = 1752192. Its totient is φ = 163680.

The previous prime is 643751. The next prime is 643781. The reversal of 643770 is 77346.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1915 + ... + 2225.

It is an arithmetic number, because the mean of its divisors is an integer number (36504).

2⁶⁴³⁷⁷⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643770, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (876096).

643770 is an abundant number, since it is smaller than the sum of its proper divisors (1108422).

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

643770 is a wasteful number, since it uses less digits than its factorization.

643770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 347 (or 344 counting only the distinct ones).

The product of its (nonzero) digits is 3528, while the sum is 27.

The square root of 643770 is about 802.3527902363. The cubic root of 643770 is about 86.3462693191.

The spelling of 643770 in words is "six hundred forty-three thousand, seven hundred seventy".