643523173 has 4 divisors (see below), whose sum is σ = 643893280. Its totient is φ = 643153068.

The previous prime is 643523171. The next prime is 643523189. The reversal of 643523173 is 371325346.

643523173 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 643523173 - 2¹ = 643523171 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 (643523171) 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, 182433 + ... + 185926.

It is an arithmetic number, because the mean of its divisors is an integer number (160973320).

Almost surely, 2^643523173 is an apocalyptic number.

It is an amenable number.

643523173 is a deficient number, since it is larger than the sum of its proper divisors (370107).

643523173 is a wasteful number, since it uses less digits than its factorization.

643523173 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370106.

The product of its digits is 45360, while the sum is 34.

The square root of 643523173 is about 25367.7585332248. The cubic root of 643523173 is about 863.3523260565.

The spelling of 643523173 in words is "six hundred forty-three million, five hundred twenty-three thousand, one hundred seventy-three".