66191810181 has 24 divisors (see below), whose sum is σ = 108703961280. Its totient is φ = 35598955392.

The previous prime is 66191810149. The next prime is 66191810183. The reversal of 66191810181 is 18101819166.

It is not a de Polignac number, because 66191810181 - 2⁵ = 66191810149 is a prime.

It is a super-2 number, since 2×66191810181² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66191810183) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13241161 + ... + 13246158.

It is an arithmetic number, because the mean of its divisors is an integer number (4529331720).

Almost surely, 2^66191810181 is an apocalyptic number.

It is an amenable number.

66191810181 is a deficient number, since it is larger than the sum of its proper divisors (42512151099).

66191810181 is a wasteful number, since it uses less digits than its factorization.

66191810181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26487353 (or 26487346 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 42.

The spelling of 66191810181 in words is "sixty-six billion, one hundred ninety-one million, eight hundred ten thousand, one hundred eighty-one".