66868091 has 2 divisors, whose sum is σ = 66868092. Its totient is φ = 66868090.

The previous prime is 66868057. The next prime is 66868117. The reversal of 66868091 is 19086866.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66868091 - 2¹⁸ = 66605947 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66868001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33434045 + 33434046.

It is an arithmetic number, because the mean of its divisors is an integer number (33434046).

Almost surely, 2^66868091 is an apocalyptic number.

66868091 is a deficient number, since it is larger than the sum of its proper divisors (1).

66868091 is an equidigital number, since it uses as much as digits as its factorization.

66868091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 124416, while the sum is 44.

The square root of 66868091 is about 8177.2911774010. The cubic root of 66868091 is about 405.8880902785. Note that the first 3 decimals are identical.

The spelling of 66868091 in words is "sixty-six million, eight hundred sixty-eight thousand, ninety-one".