643704 has 16 divisors (see below), whose sum is σ = 1609320. Its totient is φ = 214560.

The previous prime is 643703. The next prime is 643723. The reversal of 643704 is 407346.

643704 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a hoax number, since the sum of its digits (24) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (24), and also a Moran number because the ratio is a prime number: 26821 = 643704 / (6 + 4 + 3 + 7 + 0 + 4).

It is a d-powerful number, because it can be written as 6⁶ + 4³ + 7 + 3¹² + 0 + 4⁸ .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643703) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13387 + ... + 13434.

2⁶⁴³⁷⁰⁴ is an apocalyptic number.

It is an amenable number.

643704 is an abundant number, since it is smaller than the sum of its proper divisors (965616).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

643704 is a wasteful number, since it uses less digits than its factorization.

643704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26830 (or 26826 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 24.

The square root of 643704 is about 802.3116601421. The cubic root of 643704 is about 86.3433184471.

The spelling of 643704 in words is "six hundred forty-three thousand, seven hundred four".