66535406209 has 2 divisors, whose sum is σ = 66535406210. Its totient is φ = 66535406208.

The previous prime is 66535406183. The next prime is 66535406257. The reversal of 66535406209 is 90260453566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65317047184 + 1218359025 = 255572^2 + 34905^2 .

It is a cyclic number.

It is not a de Polignac number, because 66535406209 - 2¹⁵ = 66535373441 is a prime.

It is not a weakly prime, because it can be changed into another prime (66535406009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33267703104 + 33267703105.

It is an arithmetic number, because the mean of its divisors is an integer number (33267703105).

Almost surely, 2^66535406209 is an apocalyptic number.

It is an amenable number.

66535406209 is a deficient number, since it is larger than the sum of its proper divisors (1).

66535406209 is an equidigital number, since it uses as much as digits as its factorization.

66535406209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1166400, while the sum is 46.

The spelling of 66535406209 in words is "sixty-six billion, five hundred thirty-five million, four hundred six thousand, two hundred nine".