66165605 has 32 divisors (see below), whose sum is σ = 89831808. Its totient is φ = 46368000.

The previous prime is 66165601. The next prime is 66165629. The reversal of 66165605 is 50656166.

It is not a de Polignac number, because 66165605 - 2² = 66165601 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66165601) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 238727 + ... + 239003.

It is an arithmetic number, because the mean of its divisors is an integer number (2807244).

Almost surely, 2^66165605 is an apocalyptic number.

It is an amenable number.

66165605 is a deficient number, since it is larger than the sum of its proper divisors (23666203).

66165605 is a wasteful number, since it uses less digits than its factorization.

66165605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 437.

The product of its (nonzero) digits is 32400, while the sum is 35.

The square root of 66165605 is about 8134.2243022921. The cubic root of 66165605 is about 404.4617245772.

It can be divided in two parts, 6616 and 5605, that added together give a palindrome (12221).

The spelling of 66165605 in words is "sixty-six million, one hundred sixty-five thousand, six hundred five".