643259 has 4 divisors (see below), whose sum is σ = 645816. Its totient is φ = 640704.

The previous prime is 643243. The next prime is 643273. The reversal of 643259 is 952346.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 643259 - 2⁴ = 643243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643859) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 854 + ... + 1419.

It is an arithmetic number, because the mean of its divisors is an integer number (161454).

2⁶⁴³²⁵⁹ is an apocalyptic number.

643259 is a deficient number, since it is larger than the sum of its proper divisors (2557).

643259 is a wasteful number, since it uses less digits than its factorization.

643259 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2556.

The product of its digits is 6480, while the sum is 29.

The square root of 643259 is about 802.0342885438. The cubic root of 643259 is about 86.3234171497.

The spelling of 643259 in words is "six hundred forty-three thousand, two hundred fifty-nine".