643409 has 8 divisors (see below), whose sum is σ = 709632. Its totient is φ = 579600.

The previous prime is 643403. The next prime is 643421. The reversal of 643409 is 904346.

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 643409 - 2¹⁶ = 577873 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (643403) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17 + ... + 1134.

It is an arithmetic number, because the mean of its divisors is an integer number (88704).

2⁶⁴³⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

643409 is a deficient number, since it is larger than the sum of its proper divisors (66223).

643409 is a wasteful number, since it uses less digits than its factorization.

643409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1207.

The product of its (nonzero) digits is 2592, while the sum is 26.

The square root of 643409 is about 802.1277953045. The cubic root of 643409 is about 86.3301264774.

The spelling of 643409 in words is "six hundred forty-three thousand, four hundred nine".