66761139197 has 2 divisors, whose sum is σ = 66761139198. Its totient is φ = 66761139196.

The previous prime is 66761139191. The next prime is 66761139209. The reversal of 66761139197 is 79193116766.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66402074596 + 359064601 = 257686^2 + 18949^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66761139197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66761139191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33380569598 + 33380569599.

It is an arithmetic number, because the mean of its divisors is an integer number (33380569599).

Almost surely, 2^66761139197 is an apocalyptic number.

It is an amenable number.

66761139197 is a deficient number, since it is larger than the sum of its proper divisors (1).

66761139197 is an equidigital number, since it uses as much as digits as its factorization.

66761139197 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2571912, while the sum is 56.

The spelling of 66761139197 in words is "sixty-six billion, seven hundred sixty-one million, one hundred thirty-nine thousand, one hundred ninety-seven".