643427111 has 2 divisors, whose sum is σ = 643427112. Its totient is φ = 643427110.

The previous prime is 643427107. The next prime is 643427123. The reversal of 643427111 is 111724346.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 643427111 - 2² = 643427107 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643427131) 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, 321713555 + 321713556.

It is an arithmetic number, because the mean of its divisors is an integer number (321713556).

Almost surely, 2^643427111 is an apocalyptic number.

643427111 is a deficient number, since it is larger than the sum of its proper divisors (1).

643427111 is an equidigital number, since it uses as much as digits as its factorization.

643427111 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 29.

The square root of 643427111 is about 25365.8650749388. The cubic root of 643427111 is about 863.3093649109.

The spelling of 643427111 in words is "six hundred forty-three million, four hundred twenty-seven thousand, one hundred eleven".