66544333181 has 2 divisors, whose sum is σ = 66544333182. Its totient is φ = 66544333180.

The previous prime is 66544333157. The next prime is 66544333223. The reversal of 66544333181 is 18133344566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54713420281 + 11830912900 = 233909^2 + 108770^2 .

It is a cyclic number.

It is not a de Polignac number, because 66544333181 - 2³⁰ = 65470591357 is a prime.

It is a super-2 number, since 2×66544333181² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66544333151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33272166590 + 33272166591.

It is an arithmetic number, because the mean of its divisors is an integer number (33272166591).

Almost surely, 2^66544333181 is an apocalyptic number.

It is an amenable number.

66544333181 is a deficient number, since it is larger than the sum of its proper divisors (1).

66544333181 is an equidigital number, since it uses as much as digits as its factorization.

66544333181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 622080, while the sum is 44.

The spelling of 66544333181 in words is "sixty-six billion, five hundred forty-four million, three hundred thirty-three thousand, one hundred eighty-one".