643418 has 4 divisors (see below), whose sum is σ = 965130. Its totient is φ = 321708.

The previous prime is 643403. The next prime is 643421. The reversal of 643418 is 814346.

643418 is nontrivially palindromic in base 8.

643418 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in only one way, i.e., 485809 + 157609 = 697^2 + 397^2 .

It is a Curzon number.

It is a nialpdrome in base 15.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 643418.

It is an unprimeable number.

643418 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160853 + ... + 160856.

2⁶⁴³⁴¹⁸ is an apocalyptic number.

643418 is a deficient number, since it is larger than the sum of its proper divisors (321712).

643418 is a wasteful number, since it uses less digits than its factorization.

643418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321711.

The product of its digits is 2304, while the sum is 26.

The square root of 643418 is about 802.1334053635. The cubic root of 643418 is about 86.3305290039.

The spelling of 643418 in words is "six hundred forty-three thousand, four hundred eighteen".