643842133 has 4 divisors (see below), whose sum is σ = 702373248. Its totient is φ = 585311020.

The previous prime is 643842107. The next prime is 643842169. The reversal of 643842133 is 331248346.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643842133 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 (643842233) 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, 29265541 + ... + 29265562.

It is an arithmetic number, because the mean of its divisors is an integer number (175593312).

Almost surely, 2^643842133 is an apocalyptic number.

It is an amenable number.

643842133 is a deficient number, since it is larger than the sum of its proper divisors (58531115).

643842133 is a wasteful number, since it uses less digits than its factorization.

643842133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58531114.

The product of its digits is 41472, while the sum is 34.

The square root of 643842133 is about 25374.0444746201. The cubic root of 643842133 is about 863.4949416792.

The spelling of 643842133 in words is "six hundred forty-three million, eight hundred forty-two thousand, one hundred thirty-three".