66788655688765 has 16 divisors (see below), whose sum is σ = 83326567464000. Its totient is φ = 51349705418880.

The previous prime is 66788655688753. The next prime is 66788655688817. The reversal of 66788655688765 is 56788655688766.

It is not a de Polignac number, because 66788655688765 - 2³¹ = 66786508205117 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66788655688765.

It is a congruent number.

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, 2431317015 + ... + 2431344484.

It is an arithmetic number, because the mean of its divisors is an integer number (5207910466500).

Almost surely, 2^{66788655688765} is an apocalyptic number.

It is an amenable number.

66788655688765 is a deficient number, since it is larger than the sum of its proper divisors (16537911775235).

66788655688765 is a wasteful number, since it uses less digits than its factorization.

66788655688765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4862661612.

The product of its digits is 195084288000, while the sum is 91.

Subtracting from 66788655688765 its reverse (56788655688766), we obtain a palindrome (9999999999999).

The spelling of 66788655688765 in words is "sixty-six trillion, seven hundred eighty-eight billion, six hundred fifty-five million, six hundred eighty-eight thousand, seven hundred sixty-five".