643731697 has 8 divisors (see below), whose sum is σ = 737207936. Its totient is φ = 550634112.

The previous prime is 643731691. The next prime is 643731811. The reversal of 643731697 is 796137346.

643731697 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 643731697 - 2³ = 643731689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643731691) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 91008 + ... + 97825.

It is an arithmetic number, because the mean of its divisors is an integer number (92150992).

Almost surely, 2^643731697 is an apocalyptic number.

It is an amenable number.

643731697 is a deficient number, since it is larger than the sum of its proper divisors (93476239).

643731697 is a wasteful number, since it uses less digits than its factorization.

643731697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189327.

The product of its digits is 571536, while the sum is 46.

The square root of 643731697 is about 25371.8682205312. The cubic root of 643731697 is about 863.4455680956.

The spelling of 643731697 in words is "six hundred forty-three million, seven hundred thirty-one thousand, six hundred ninety-seven".