66518281566 has 32 divisors (see below), whose sum is σ = 161256441600. Its totient is φ = 20157054840.

The previous prime is 66518281523. The next prime is 66518281579.

66518281566 is a `hidden beast` number, since 6 + 6 + 51 + 8 + 28 + 1 + 566 = 666.

66518281566 is nontrivially palindromic in base 10.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55991226 + ... + 55992413.

It is an arithmetic number, because the mean of its divisors is an integer number (5039263800).

Almost surely, 2^66518281566 is an apocalyptic number.

66518281566 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

66518281566 is an abundant number, since it is smaller than the sum of its proper divisors (94738160034).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66518281566 is a wasteful number, since it uses less digits than its factorization.

66518281566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111983661 (or 111983655 counting only the distinct ones).

The product of its digits is 4147200, while the sum is 54.

The spelling of 66518281566 in words is "sixty-six billion, five hundred eighteen million, two hundred eighty-one thousand, five hundred sixty-six".