66245665 has 16 divisors (see below), whose sum is σ = 80981712. Its totient is φ = 52015104.

The previous prime is 66245659. The next prime is 66245713. The reversal of 66245665 is 56654266.

66245665 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 1459264 + 64786401 = 1208^2 + 8049^2 .

It is a cyclic number.

It is not a de Polignac number, because 66245665 - 2⁵ = 66245633 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 65947 + ... + 66943.

It is an arithmetic number, because the mean of its divisors is an integer number (5061357).

Almost surely, 2^66245665 is an apocalyptic number.

It is an amenable number.

66245665 is a deficient number, since it is larger than the sum of its proper divisors (14736047).

66245665 is a wasteful number, since it uses less digits than its factorization.

66245665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1236.

The product of its digits is 259200, while the sum is 40.

The square root of 66245665 is about 8139.1439967603. The cubic root of 66245665 is about 404.6247909422.

The spelling of 66245665 in words is "sixty-six million, two hundred forty-five thousand, six hundred sixty-five".