66711811765 has 24 divisors (see below), whose sum is σ = 84107318400. Its totient is φ = 50792109984.

The previous prime is 66711811741. The next prime is 66711811781. The reversal of 66711811765 is 56711811766.

It is a de Polignac number, because none of the positive numbers 2^k-66711811765 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 462984 + ... + 589726.

It is an arithmetic number, because the mean of its divisors is an integer number (3504471600).

Almost surely, 2^66711811765 is an apocalyptic number.

It is an amenable number.

66711811765 is a deficient number, since it is larger than the sum of its proper divisors (17395506635).

66711811765 is a wasteful number, since it uses less digits than its factorization.

66711811765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126993 (or 126970 counting only the distinct ones).

The product of its digits is 423360, while the sum is 49.

Subtracting from 66711811765 its reverse (56711811766), we obtain a palindrome (9999999999).

The spelling of 66711811765 in words is "sixty-six billion, seven hundred eleven million, eight hundred eleven thousand, seven hundred sixty-five".