66385181 has 2 divisors, whose sum is σ = 66385182. Its totient is φ = 66385180.

The previous prime is 66385171. The next prime is 66385211. The reversal of 66385181 is 18158366.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40119556 + 26265625 = 6334^2 + 5125^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66385181 is a prime.

It is a super-2 number, since 2×66385181² = 8813984512805522, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66385171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33192590 + 33192591.

It is an arithmetic number, because the mean of its divisors is an integer number (33192591).

Almost surely, 2^66385181 is an apocalyptic number.

It is an amenable number.

66385181 is a deficient number, since it is larger than the sum of its proper divisors (1).

66385181 is an equidigital number, since it uses as much as digits as its factorization.

66385181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34560, while the sum is 38.

The square root of 66385181 is about 8147.7101691211. The cubic root of 66385181 is about 404.9086437238.

It can be divided in two parts, 66385 and 181, that added together give a palindrome (66566).

The spelling of 66385181 in words is "sixty-six million, three hundred eighty-five thousand, one hundred eighty-one".