643622011 has 2 divisors, whose sum is σ = 643622012. Its totient is φ = 643622010.

The previous prime is 643622009. The next prime is 643622069. The reversal of 643622011 is 110226346.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 643622011 - 2¹ = 643622009 is a prime.

Together with 643622009, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (643622081) 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, 321811005 + 321811006.

It is an arithmetic number, because the mean of its divisors is an integer number (321811006).

Almost surely, 2^643622011 is an apocalyptic number.

643622011 is a deficient number, since it is larger than the sum of its proper divisors (1).

643622011 is an equidigital number, since it uses as much as digits as its factorization.

643622011 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 25.

The square root of 643622011 is about 25369.7065611725. The cubic root of 643622011 is about 863.3965242312.

Adding to 643622011 its reverse (110226346), we get a palindrome (753848357).

The spelling of 643622011 in words is "six hundred forty-three million, six hundred twenty-two thousand, eleven".