643401611 has 2 divisors, whose sum is σ = 643401612. Its totient is φ = 643401610.

The previous prime is 643401527. The next prime is 643401631. The reversal of 643401611 is 116104346.

643401611 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 is a cyclic number.

It is not a de Polignac number, because 643401611 - 2¹⁰ = 643400587 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (643401631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321700805 + 321700806.

It is an arithmetic number, because the mean of its divisors is an integer number (321700806).

Almost surely, 2^643401611 is an apocalyptic number.

643401611 is a deficient number, since it is larger than the sum of its proper divisors (1).

643401611 is an equidigital number, since it uses as much as digits as its factorization.

643401611 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 643401611 is about 25365.3624259540. The cubic root of 643401611 is about 863.2979600036.

Adding to 643401611 its reverse (116104346), we get a palindrome (759505957).

The spelling of 643401611 in words is "six hundred forty-three million, four hundred one thousand, six hundred eleven".