643571263 has 2 divisors, whose sum is σ = 643571264. Its totient is φ = 643571262.

The previous prime is 643571231. The next prime is 643571267. The reversal of 643571263 is 362175346.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 643571263 - 2⁵ = 643571231 is a prime.

It is equal to p_33476554 and since 643571263 and 33476554 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643571267) 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, 321785631 + 321785632.

It is an arithmetic number, because the mean of its divisors is an integer number (321785632).

Almost surely, 2^643571263 is an apocalyptic number.

643571263 is a deficient number, since it is larger than the sum of its proper divisors (1).

643571263 is an equidigital number, since it uses as much as digits as its factorization.

643571263 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90720, while the sum is 37.

The square root of 643571263 is about 25368.7063722217. The cubic root of 643571263 is about 863.3738314096.

The spelling of 643571263 in words is "six hundred forty-three million, five hundred seventy-one thousand, two hundred sixty-three".