643799459 has 4 divisors (see below), whose sum is σ = 644323680. Its totient is φ = 643275240.

The previous prime is 643799441. The next prime is 643799461. The reversal of 643799459 is 954997346.

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 643799459 - 2¹² = 643795363 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643799479) 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, 260264 + ... + 262725.

It is an arithmetic number, because the mean of its divisors is an integer number (161080920).

Almost surely, 2^643799459 is an apocalyptic number.

643799459 is a deficient number, since it is larger than the sum of its proper divisors (524221).

643799459 is a wasteful number, since it uses less digits than its factorization.

643799459 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 524220.

The product of its digits is 7348320, while the sum is 56.

The square root of 643799459 is about 25373.2035620258. The cubic root of 643799459 is about 863.4758637120.

The spelling of 643799459 in words is "six hundred forty-three million, seven hundred ninety-nine thousand, four hundred fifty-nine".