643171667 has 2 divisors, whose sum is σ = 643171668. Its totient is φ = 643171666.

The previous prime is 643171651. The next prime is 643171673. The reversal of 643171667 is 766171346.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 643171667 - 2⁴ = 643171651 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (643171267) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321585833 + 321585834.

It is an arithmetic number, because the mean of its divisors is an integer number (321585834).

Almost surely, 2^643171667 is an apocalyptic number.

643171667 is a deficient number, since it is larger than the sum of its proper divisors (1).

643171667 is an equidigital number, since it uses as much as digits as its factorization.

643171667 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 127008, while the sum is 41.

The square root of 643171667 is about 25360.8293831255. The cubic root of 643171667 is about 863.1951036456.

The spelling of 643171667 in words is "six hundred forty-three million, one hundred seventy-one thousand, six hundred sixty-seven".