66255805581 has 32 divisors (see below), whose sum is σ = 104444583936. Its totient is φ = 36559512000.

The previous prime is 66255805573. The next prime is 66255805601. The reversal of 66255805581 is 18550855266.

It is not a de Polignac number, because 66255805581 - 2³ = 66255805573 is a prime.

It is a super-2 number, since 2×66255805581² (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 (66255805571) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 189726 + ... + 410496.

It is an arithmetic number, because the mean of its divisors is an integer number (3263893248).

Almost surely, 2^66255805581 is an apocalyptic number.

It is an amenable number.

66255805581 is a deficient number, since it is larger than the sum of its proper divisors (38188778355).

66255805581 is a wasteful number, since it uses less digits than its factorization.

66255805581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221273.

The product of its (nonzero) digits is 2880000, while the sum is 51.

The spelling of 66255805581 in words is "sixty-six billion, two hundred fifty-five million, eight hundred five thousand, five hundred eighty-one".