66612665 has 16 divisors (see below), whose sum is σ = 91764480. Its totient is φ = 45472320.

The previous prime is 66612653. The next prime is 66612701. The reversal of 66612665 is 56621666.

It is not a de Polignac number, because 66612665 - 2¹⁰ = 66611641 is a prime.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 3860 + ... + 12170.

It is an arithmetic number, because the mean of its divisors is an integer number (5735280).

Almost surely, 2^66612665 is an apocalyptic number.

It is an amenable number.

66612665 is a deficient number, since it is larger than the sum of its proper divisors (25151815).

66612665 is a wasteful number, since it uses less digits than its factorization.

66612665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8552.

The product of its digits is 77760, while the sum is 38.

The square root of 66612665 is about 8161.6582261205. The cubic root of 66612665 is about 405.3706204487.

Subtracting from 66612665 its reverse (56621666), we obtain a palindrome (9990999).

It can be divided in two parts, 666 and 12665, that added together give a palindrome (13331).

The spelling of 66612665 in words is "sixty-six million, six hundred twelve thousand, six hundred sixty-five".