66381181 has 2 divisors, whose sum is σ = 66381182. Its totient is φ = 66381180.

The previous prime is 66381149. The next prime is 66381187. The reversal of 66381181 is 18118366.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 64545156 + 1836025 = 8034^2 + 1355^2 .

It is a cyclic number.

It is not a de Polignac number, because 66381181 - 2⁵ = 66381149 is a prime.

It is a super-2 number, since 2×66381181² = 8812922381909522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66381187) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33190590 + 33190591.

It is an arithmetic number, because the mean of its divisors is an integer number (33190591).

Almost surely, 2^66381181 is an apocalyptic number.

It is an amenable number.

66381181 is a deficient number, since it is larger than the sum of its proper divisors (1).

66381181 is an equidigital number, since it uses as much as digits as its factorization.

66381181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6912, while the sum is 34.

The square root of 66381181 is about 8147.4646976836. The cubic root of 66381181 is about 404.9005110498.

The spelling of 66381181 in words is "sixty-six million, three hundred eighty-one thousand, one hundred eighty-one".