643428759 has 4 divisors (see below), whose sum is σ = 857905016. Its totient is φ = 428952504.

The previous prime is 643428727. The next prime is 643428761. The reversal of 643428759 is 957824346.

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

It is not a de Polignac number, because 643428759 - 2⁵ = 643428727 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 (643428719) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107238124 + ... + 107238129.

It is an arithmetic number, because the mean of its divisors is an integer number (214476254).

Almost surely, 2^643428759 is an apocalyptic number.

643428759 is a deficient number, since it is larger than the sum of its proper divisors (214476257).

643428759 is a wasteful number, since it uses less digits than its factorization.

643428759 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214476256.

The product of its digits is 1451520, while the sum is 48.

The square root of 643428759 is about 25365.8975595188. The cubic root of 643428759 is about 863.3101019706.

It can be divided in two parts, 6434287 and 59, that added together give a palindrome (6434346).

The spelling of 643428759 in words is "six hundred forty-three million, four hundred twenty-eight thousand, seven hundred fifty-nine".