66539018993 has 2 divisors, whose sum is σ = 66539018994. Its totient is φ = 66539018992.

The previous prime is 66539018981. The next prime is 66539019059. The reversal of 66539018993 is 39981093566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 38954127424 + 27584891569 = 197368^2 + 166087^2 .

It is a cyclic number.

It is not a de Polignac number, because 66539018993 - 2²⁶ = 66471910129 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (66539018093) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33269509496 + 33269509497.

It is an arithmetic number, because the mean of its divisors is an integer number (33269509497).

Almost surely, 2^66539018993 is an apocalyptic number.

It is an amenable number.

66539018993 is a deficient number, since it is larger than the sum of its proper divisors (1).

66539018993 is an equidigital number, since it uses as much as digits as its factorization.

66539018993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9447840, while the sum is 59.

The spelling of 66539018993 in words is "sixty-six billion, five hundred thirty-nine million, eighteen thousand, nine hundred ninety-three".