643875 has 32 divisors (see below), whose sum is σ = 1145664. Its totient is φ = 320000.

The previous prime is 643873. The next prime is 643879. The reversal of 643875 is 578346.

643875 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 643875 - 2¹ = 643873 is a prime.

It is an Ulam number.

Its product of digits (20160) is a multiple of the sum of its prime divisors (126).

643875 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (643873) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6325 + ... + 6425.

It is an arithmetic number, because the mean of its divisors is an integer number (35802).

2⁶⁴³⁸⁷⁵ is an apocalyptic number.

643875 is a deficient number, since it is larger than the sum of its proper divisors (501789).

643875 is a wasteful number, since it uses less digits than its factorization.

643875 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136 (or 126 counting only the distinct ones).

The product of its digits is 20160, while the sum is 33.

The square root of 643875 is about 802.4182201321. The cubic root of 643875 is about 86.3509634725.

Adding to 643875 its reverse (578346), we get a palindrome (1222221).

The spelling of 643875 in words is "six hundred forty-three thousand, eight hundred seventy-five".