66171111720 has 64 divisors (see below), whose sum is σ = 226872385920. Its totient is φ = 15124825344.

The previous prime is 66171111689. The next prime is 66171111737. The reversal of 66171111720 is 2711117166.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 39386727 + ... + 39388406.

It is an arithmetic number, because the mean of its divisors is an integer number (3544881030).

Almost surely, 2^66171111720 is an apocalyptic number.

66171111720 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66171111720 is an abundant number, since it is smaller than the sum of its proper divisors (160701274200).

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

66171111720 is a wasteful number, since it uses less digits than its factorization.

66171111720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78775154 (or 78775150 counting only the distinct ones).

The product of its (nonzero) digits is 3528, while the sum is 33.

Adding to 66171111720 its reverse (2711117166), we get a palindrome (68882228886).

The spelling of 66171111720 in words is "sixty-six billion, one hundred seventy-one million, one hundred eleven thousand, seven hundred twenty".