669661807 has 4 divisors (see below), whose sum is σ = 709053696. Its totient is φ = 630269920.

The previous prime is 669661801. The next prime is 669661819. The reversal of 669661807 is 708166966.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 669661807 - 2¹¹ = 669659759 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669661801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19695919 + ... + 19695952.

It is an arithmetic number, because the mean of its divisors is an integer number (177263424).

Almost surely, 2^669661807 is an apocalyptic number.

669661807 is a deficient number, since it is larger than the sum of its proper divisors (39391889).

669661807 is a wasteful number, since it uses less digits than its factorization.

669661807 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39391888.

The product of its (nonzero) digits is 653184, while the sum is 49.

The square root of 669661807 is about 25877.8246187735. The cubic root of 669661807 is about 874.8867584607.

The spelling of 669661807 in words is "six hundred sixty-nine million, six hundred sixty-one thousand, eight hundred seven".