66506181 has 24 divisors (see below), whose sum is σ = 103475520. Its totient is φ = 37884672.

The previous prime is 66506161. The next prime is 66506189. The reversal of 66506181 is 18160566.

It is not a de Polignac number, because 66506181 - 2⁶ = 66506117 is a prime.

It is a super-2 number, since 2×66506181² = 8846144222409522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66506189) 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, 71125 + ... + 72053.

It is an arithmetic number, because the mean of its divisors is an integer number (4311480).

Almost surely, 2^66506181 is an apocalyptic number.

It is an amenable number.

66506181 is a deficient number, since it is larger than the sum of its proper divisors (36969339).

66506181 is a wasteful number, since it uses less digits than its factorization.

66506181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1433 (or 1426 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 66506181 is about 8155.1321877699. The cubic root of 66506181 is about 405.1545028560.

The spelling of 66506181 in words is "sixty-six million, five hundred six thousand, one hundred eighty-one".