66788817 has 8 divisors (see below), whose sum is σ = 89200896. Its totient is φ = 44451312.

The previous prime is 66788809. The next prime is 66788831. The reversal of 66788817 is 71888766.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66788817 - 2³ = 66788809 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66788817.

It is not an unprimeable number, because it can be changed into a prime (66788017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16518 + ... + 20159.

It is an arithmetic number, because the mean of its divisors is an integer number (11150112).

Almost surely, 2^66788817 is an apocalyptic number.

It is an amenable number.

66788817 is a deficient number, since it is larger than the sum of its proper divisors (22412079).

66788817 is a wasteful number, since it uses less digits than its factorization.

66788817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37287.

The product of its digits is 903168, while the sum is 51.

The square root of 66788817 is about 8172.4425357417. The cubic root of 66788817 is about 405.7276296078.

Subtracting from 66788817 its sum of digits (51), we obtain a palindrome (66788766).

The spelling of 66788817 in words is "sixty-six million, seven hundred eighty-eight thousand, eight hundred seventeen".