66442181 has 24 divisors (see below), whose sum is σ = 75753216. Its totient is φ = 58181760.

The previous prime is 66442177. The next prime is 66442199. The reversal of 66442181 is 18124466.

It is not a de Polignac number, because 66442181 - 2² = 66442177 is a prime.

It is a super-2 number, since 2×66442181² = 8829126832073522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66442151) 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 in 23 ways as a sum of consecutive naturals, for example, 297836 + ... + 298058.

It is an arithmetic number, because the mean of its divisors is an integer number (3156384).

Almost surely, 2^66442181 is an apocalyptic number.

It is an amenable number.

66442181 is a deficient number, since it is larger than the sum of its proper divisors (9311035).

66442181 is a wasteful number, since it uses less digits than its factorization.

66442181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333 (or 320 counting only the distinct ones).

The product of its digits is 9216, while the sum is 32.

The square root of 66442181 is about 8151.2073338862. The cubic root of 66442181 is about 405.0244988482.

The spelling of 66442181 in words is "sixty-six million, four hundred forty-two thousand, one hundred eighty-one".