66897829981 has 2 divisors, whose sum is σ = 66897829982. Its totient is φ = 66897829980.

The previous prime is 66897829937. The next prime is 66897830011. The reversal of 66897829981 is 18992879866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66850688025 + 47141956 = 258555^2 + 6866^2 .

It is a cyclic number.

It is not a de Polignac number, because 66897829981 - 2¹⁷ = 66897698909 is a prime.

It is a super-2 number, since 2×66897829981² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66897829181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33448914990 + 33448914991.

It is an arithmetic number, because the mean of its divisors is an integer number (33448914991).

Almost surely, 2^66897829981 is an apocalyptic number.

It is an amenable number.

66897829981 is a deficient number, since it is larger than the sum of its proper divisors (1).

66897829981 is an equidigital number, since it uses as much as digits as its factorization.

66897829981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 188116992, while the sum is 73.

The spelling of 66897829981 in words is "sixty-six billion, eight hundred ninety-seven million, eight hundred twenty-nine thousand, nine hundred eighty-one".