643389 has 4 divisors (see below), whose sum is σ = 857856. Its totient is φ = 428924.

The previous prime is 643373. The next prime is 643403. The reversal of 643389 is 983346.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 643389 - 2⁴ = 643373 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643369) 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, 107229 + ... + 107234.

It is an arithmetic number, because the mean of its divisors is an integer number (214464).

2⁶⁴³³⁸⁹ is an apocalyptic number.

It is an amenable number.

643389 is a deficient number, since it is larger than the sum of its proper divisors (214467).

643389 is a wasteful number, since it uses less digits than its factorization.

643389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214466.

The product of its digits is 15552, while the sum is 33.

The square root of 643389 is about 802.1153283662. The cubic root of 643389 is about 86.3292319606.

The spelling of 643389 in words is "six hundred forty-three thousand, three hundred eighty-nine".