66317581 has 16 divisors (see below), whose sum is σ = 77091840. Its totient is φ = 56412720.

The previous prime is 66317557. The next prime is 66317597. The reversal of 66317581 is 18571366.

It is a cyclic number.

It is not a de Polignac number, because 66317581 - 2²⁵ = 32763149 is a prime.

It is a super-2 number, since 2×66317581² = 8796043099383122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66317581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66317081) 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 15 ways as a sum of consecutive naturals, for example, 15436 + ... + 19258.

It is an arithmetic number, because the mean of its divisors is an integer number (4818240).

Almost surely, 2^66317581 is an apocalyptic number.

It is an amenable number.

66317581 is a deficient number, since it is larger than the sum of its proper divisors (10774259).

66317581 is a wasteful number, since it uses less digits than its factorization.

66317581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3936.

The product of its digits is 30240, while the sum is 37.

The square root of 66317581 is about 8143.5607077003. The cubic root of 66317581 is about 404.7711576159.

The spelling of 66317581 in words is "sixty-six million, three hundred seventeen thousand, five hundred eighty-one".