66666696997 has 2 divisors, whose sum is σ = 66666696998. Its totient is φ = 66666696996.

The previous prime is 66666696947. The next prime is 66666697037. The reversal of 66666696997 is 79969666666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66375277956 + 291419041 = 257634^2 + 17071^2 .

It is a cyclic number.

It is not a de Polignac number, because 66666696997 - 2⁷ = 66666696869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66666696907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33333348498 + 33333348499.

It is an arithmetic number, because the mean of its divisors is an integer number (33333348499).

Almost surely, 2^66666696997 is an apocalyptic number.

It is an amenable number.

66666696997 is a deficient number, since it is larger than the sum of its proper divisors (1).

66666696997 is an equidigital number, since it uses as much as digits as its factorization.

66666696997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1428513408, while the sum is 76.

The spelling of 66666696997 in words is "sixty-six billion, six hundred sixty-six million, six hundred ninety-six thousand, nine hundred ninety-seven".