66681133 has 2 divisors, whose sum is σ = 66681134. Its totient is φ = 66681132.

The previous prime is 66681107. The next prime is 66681143. The reversal of 66681133 is 33118666.

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., 54199044 + 12482089 = 7362^2 + 3533^2 .

It is a cyclic number.

It is not a de Polignac number, because 66681133 - 2¹³ = 66672941 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66681143) 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, 33340566 + 33340567.

It is an arithmetic number, because the mean of its divisors is an integer number (33340567).

Almost surely, 2^66681133 is an apocalyptic number.

It is an amenable number.

66681133 is a deficient number, since it is larger than the sum of its proper divisors (1).

66681133 is an equidigital number, since it uses as much as digits as its factorization.

66681133 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 34.

The square root of 66681133 is about 8165.8516396026. The cubic root of 66681133 is about 405.5094599709.

Adding to 66681133 its reverse (33118666), we get a palindrome (99799799).

The spelling of 66681133 in words is "sixty-six million, six hundred eighty-one thousand, one hundred thirty-three".