66752518581 has 32 divisors (see below), whose sum is σ = 116665958400. Its totient is φ = 36913831920.

The previous prime is 66752518577. The next prime is 66752518583. The reversal of 66752518581 is 18581525766.

66752518581 is a `hidden beast` number, since 6 + 6 + 7 + 5 + 2 + 51 + 8 + 581 = 666.

It is not a de Polignac number, because 66752518581 - 2² = 66752518577 is a prime.

It is a super-2 number, since 2×66752518581² (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 (66752518583) 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 31 ways as a sum of consecutive naturals, for example, 5690721 + ... + 5702438.

It is an arithmetic number, because the mean of its divisors is an integer number (3645811200).

Almost surely, 2^66752518581 is an apocalyptic number.

It is an amenable number.

66752518581 is a deficient number, since it is larger than the sum of its proper divisors (49913439819).

66752518581 is a wasteful number, since it uses less digits than its factorization.

66752518581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11393206 (or 11393200 counting only the distinct ones).

The product of its digits is 4032000, while the sum is 54.

The spelling of 66752518581 in words is "sixty-six billion, seven hundred fifty-two million, five hundred eighteen thousand, five hundred eighty-one".