643711 has 4 divisors (see below), whose sum is σ = 646624. Its totient is φ = 640800.

The previous prime is 643703. The next prime is 643723. The reversal of 643711 is 117346.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 643711 - 2³ = 643703 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643751) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1095 + ... + 1576.

It is an arithmetic number, because the mean of its divisors is an integer number (161656).

2⁶⁴³⁷¹¹ is an apocalyptic number.

643711 is a deficient number, since it is larger than the sum of its proper divisors (2913).

643711 is a wasteful number, since it uses less digits than its factorization.

643711 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2912.

The product of its digits is 504, while the sum is 22.

The square root of 643711 is about 802.3160225248. The cubic root of 643711 is about 86.3436314279.

It can be divided in two parts, 6437 and 11, that multiplied together give a palindrome (70807).

The spelling of 643711 in words is "six hundred forty-three thousand, seven hundred eleven".