66568181 has 2 divisors, whose sum is σ = 66568182. Its totient is φ = 66568180.

The previous prime is 66568127. The next prime is 66568211. The reversal of 66568181 is 18186566.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 53787556 + 12780625 = 7334^2 + 3575^2 .

It is a cyclic number.

It is not a de Polignac number, because 66568181 - 2¹⁰ = 66567157 is a prime.

It is a super-2 number, since 2×66568181² = 8862645443297522, 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 (66568781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33284090 + 33284091.

It is an arithmetic number, because the mean of its divisors is an integer number (33284091).

Almost surely, 2^66568181 is an apocalyptic number.

It is an amenable number.

66568181 is a deficient number, since it is larger than the sum of its proper divisors (1).

66568181 is an equidigital number, since it uses as much as digits as its factorization.

66568181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69120, while the sum is 41.

The square root of 66568181 is about 8158.9325894997. The cubic root of 66568181 is about 405.2803647282.

The spelling of 66568181 in words is "sixty-six million, five hundred sixty-eight thousand, one hundred eighty-one".