643511445197 has 2 divisors, whose sum is σ = 643511445198. Its totient is φ = 643511445196.

The previous prime is 643511445169. The next prime is 643511445217. The reversal of 643511445197 is 791544115346.

643511445197 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 351624094441 + 291887350756 = 592979^2 + 540266^2 .

It is a cyclic number.

It is not a de Polignac number, because 643511445197 - 2⁸ = 643511444941 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643511445127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321755722598 + 321755722599.

It is an arithmetic number, because the mean of its divisors is an integer number (321755722599).

Almost surely, 2^643511445197 is an apocalyptic number.

It is an amenable number.

643511445197 is a deficient number, since it is larger than the sum of its proper divisors (1).

643511445197 is an equidigital number, since it uses as much as digits as its factorization.

643511445197 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1814400, while the sum is 50.

The spelling of 643511445197 in words is "six hundred forty-three billion, five hundred eleven million, four hundred forty-five thousand, one hundred ninety-seven".