66666666643 has 2 divisors, whose sum is σ = 66666666644. Its totient is φ = 66666666642.

The previous prime is 66666666589. The next prime is 66666666667. The reversal of 66666666643 is 34666666666.

66666666643 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 66666666643 - 2²⁵ = 66633112211 is a prime.

It is a nialpdrome in base 10.

It is not a weakly prime, because it can be changed into another prime (66666666343) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33333333321 + 33333333322.

It is an arithmetic number, because the mean of its divisors is an integer number (33333333322).

Almost surely, 2^66666666643 is an apocalyptic number.

66666666643 is a deficient number, since it is larger than the sum of its proper divisors (1).

66666666643 is an equidigital number, since it uses as much as digits as its factorization.

66666666643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120932352, while the sum is 61.

The spelling of 66666666643 in words is "sixty-six billion, six hundred sixty-six million, six hundred sixty-six thousand, six hundred forty-three".