66439665 has 48 divisors (see below), whose sum is σ = 120347136. Its totient is φ = 33868800.

The previous prime is 66439661. The next prime is 66439691. The reversal of 66439665 is 56693466.

It is not a de Polignac number, because 66439665 - 2² = 66439661 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

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 66439665.

It is not an unprimeable number, because it can be changed into a prime (66439661) 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 47 ways as a sum of consecutive naturals, for example, 135070 + ... + 135560.

It is an arithmetic number, because the mean of its divisors is an integer number (2507232).

Almost surely, 2^66439665 is an apocalyptic number.

It is an amenable number.

66439665 is a deficient number, since it is larger than the sum of its proper divisors (53907471).

66439665 is a wasteful number, since it uses less digits than its factorization.

66439665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 630 (or 627 counting only the distinct ones).

The product of its digits is 699840, while the sum is 45.

The square root of 66439665 is about 8151.0529994596. The cubic root of 66439665 is about 405.0193863605.

The spelling of 66439665 in words is "sixty-six million, four hundred thirty-nine thousand, six hundred sixty-five".