66765040581 has 16 divisors (see below), whose sum is σ = 91586385344. Its totient is φ = 43245062784.

The previous prime is 66765040561. The next prime is 66765040583. The reversal of 66765040581 is 18504056766.

It is not a de Polignac number, because 66765040581 - 2¹¹ = 66765038533 is a prime.

It is a super-2 number, since 2×66765040581² (a number of 22 digits) 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 66765040581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66765040583) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2260426 + ... + 2289771.

It is an arithmetic number, because the mean of its divisors is an integer number (5724149084).

Almost surely, 2^66765040581 is an apocalyptic number.

It is an amenable number.

66765040581 is a deficient number, since it is larger than the sum of its proper divisors (24821344763).

66765040581 is a wasteful number, since it uses less digits than its factorization.

66765040581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4550340.

The product of its (nonzero) digits is 1209600, while the sum is 48.

The spelling of 66765040581 in words is "sixty-six billion, seven hundred sixty-five million, forty thousand, five hundred eighty-one".