643469173 has 2 divisors, whose sum is σ = 643469174. Its totient is φ = 643469172.

The previous prime is 643469171. The next prime is 643469207. The reversal of 643469173 is 371964346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 465566929 + 177902244 = 21577^2 + 13338^2 .

It is a cyclic number.

It is not a de Polignac number, because 643469173 - 2¹ = 643469171 is a prime.

Together with 643469171, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643469171) 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 as a sum of consecutive naturals, namely, 321734586 + 321734587.

It is an arithmetic number, because the mean of its divisors is an integer number (321734587).

Almost surely, 2^643469173 is an apocalyptic number.

It is an amenable number.

643469173 is a deficient number, since it is larger than the sum of its proper divisors (1).

643469173 is an equidigital number, since it uses as much as digits as its factorization.

643469173 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 326592, while the sum is 43.

The square root of 643469173 is about 25366.6941677468. The cubic root of 643469173 is about 863.3281765352.

The spelling of 643469173 in words is "six hundred forty-three million, four hundred sixty-nine thousand, one hundred seventy-three".