643445 has 8 divisors (see below), whose sum is σ = 842400. Its totient is φ = 467920.

The previous prime is 643439. The next prime is 643453. The reversal of 643445 is 544346.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 643445 - 2⁴ = 643429 is a prime.

It is an Ulam number.

It is a congruent 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 7 ways as a sum of consecutive naturals, for example, 5795 + ... + 5904.

It is an arithmetic number, because the mean of its divisors is an integer number (105300).

2⁶⁴³⁴⁴⁵ is an apocalyptic number.

It is an amenable number.

643445 is a deficient number, since it is larger than the sum of its proper divisors (198955).

643445 is a wasteful number, since it uses less digits than its factorization.

643445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11715.

The product of its digits is 5760, while the sum is 26.

The square root of 643445 is about 802.1502353051. The cubic root of 643445 is about 86.3317365609.

Subtracting from 643445 its reverse (544346), we obtain a palindrome (99099).

The spelling of 643445 in words is "six hundred forty-three thousand, four hundred forty-five".