66655665 has 24 divisors (see below), whose sum is σ = 115727040. Its totient is φ = 35491104.

The previous prime is 66655661. The next prime is 66655669. The reversal of 66655665 is 56655666.

It is an interprime number because it is at equal distance from previous prime (66655661) and next prime (66655669).

It is not a de Polignac number, because 66655665 - 2² = 66655661 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 66655665.

It is not an unprimeable number, because it can be changed into a prime (66655661) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 49876 + ... + 51194.

It is an arithmetic number, because the mean of its divisors is an integer number (4821960).

Almost surely, 2^66655665 is an apocalyptic number.

It is an amenable number.

66655665 is a deficient number, since it is larger than the sum of its proper divisors (49071375).

66655665 is a wasteful number, since it uses less digits than its factorization.

66655665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2453 (or 2450 counting only the distinct ones).

The product of its digits is 972000, while the sum is 45.

The square root of 66655665 is about 8164.2920697388. The cubic root of 66655665 is about 405.4578270248.

Subtracting from 66655665 its reverse (56655666), we obtain a palindrome (9999999).

The spelling of 66655665 in words is "sixty-six million, six hundred fifty-five thousand, six hundred sixty-five".