66999510197 has 2 divisors, whose sum is σ = 66999510198. Its totient is φ = 66999510196.

The previous prime is 66999510191. The next prime is 66999510217. The reversal of 66999510197 is 79101599966.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 62037857476 + 4961652721 = 249074^2 + 70439^2 .

It is a cyclic number.

It is not a de Polignac number, because 66999510197 - 2⁴ = 66999510181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66999510191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33499755098 + 33499755099.

It is an arithmetic number, because the mean of its divisors is an integer number (33499755099).

Almost surely, 2^66999510197 is an apocalyptic number.

It is an amenable number.

66999510197 is a deficient number, since it is larger than the sum of its proper divisors (1).

66999510197 is an equidigital number, since it uses as much as digits as its factorization.

66999510197 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8266860, while the sum is 62.

The spelling of 66999510197 in words is "sixty-six billion, nine hundred ninety-nine million, five hundred ten thousand, one hundred ninety-seven".