66771306891 has 24 divisors (see below), whose sum is σ = 97678316736. Its totient is φ = 43946866800.

The previous prime is 66771306863. The next prime is 66771306907. The reversal of 66771306891 is 19860317766.

It is a happy number.

It is not a de Polignac number, because 66771306891 - 2²³ = 66762918283 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66771306191) 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 23 ways as a sum of consecutive naturals, for example, 1053096 + ... + 1114698.

It is an arithmetic number, because the mean of its divisors is an integer number (4069929864).

Almost surely, 2^66771306891 is an apocalyptic number.

66771306891 is a deficient number, since it is larger than the sum of its proper divisors (30907009845).

66771306891 is a wasteful number, since it uses less digits than its factorization.

66771306891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63143 (or 63140 counting only the distinct ones).

The product of its (nonzero) digits is 2286144, while the sum is 54.

The spelling of 66771306891 in words is "sixty-six billion, seven hundred seventy-one million, three hundred six thousand, eight hundred ninety-one".