66504181 has 2 divisors, whose sum is σ = 66504182. Its totient is φ = 66504180.

The previous prime is 66504169. The next prime is 66504197. The reversal of 66504181 is 18140566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66161956 + 342225 = 8134^2 + 585^2 .

It is a cyclic number.

It is not a de Polignac number, because 66504181 - 2⁵ = 66504149 is a prime.

It is a super-2 number, since 2×66504181² = 8845612180961522, which contains 22 as substring.

It is a Chen prime.

It is equal to p_3924265 and since 66504181 and 3924265 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66504121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33252090 + 33252091.

It is an arithmetic number, because the mean of its divisors is an integer number (33252091).

Almost surely, 2^66504181 is an apocalyptic number.

It is an amenable number.

66504181 is a deficient number, since it is larger than the sum of its proper divisors (1).

66504181 is an equidigital number, since it uses as much as digits as its factorization.

66504181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 66504181 is about 8155.0095646786. The cubic root of 66504181 is about 405.1504414935.

The spelling of 66504181 in words is "sixty-six million, five hundred four thousand, one hundred eighty-one".