643935 has 8 divisors (see below), whose sum is σ = 1030320. Its totient is φ = 343424.

The previous prime is 643927. The next prime is 643949. The reversal of 643935 is 539346.

It is a happy number.

643935 is nontrivially palindromic in base 7.

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

It is a cyclic number.

It is not a de Polignac number, because 643935 - 2³ = 643927 is a prime.

643935 is a lucky number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21450 + ... + 21479.

It is an arithmetic number, because the mean of its divisors is an integer number (128790).

2⁶⁴³⁹³⁵ is an apocalyptic number.

643935 is a deficient number, since it is larger than the sum of its proper divisors (386385).

643935 is a wasteful number, since it uses less digits than its factorization.

643935 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42937.

The product of its digits is 9720, while the sum is 30.

The square root of 643935 is about 802.4556062487. The cubic root of 643935 is about 86.3536456167.

The spelling of 643935 in words is "six hundred forty-three thousand, nine hundred thirty-five".