669876521 has 4 divisors (see below), whose sum is σ = 705133200. Its totient is φ = 634619844.

The previous prime is 669876511. The next prime is 669876523. The reversal of 669876521 is 125678966.

669876521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 669876521 - 2⁶ = 669876457 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 669876521.

It is not an unprimeable number, because it can be changed into a prime (669876523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17628311 + ... + 17628348.

It is an arithmetic number, because the mean of its divisors is an integer number (176283300).

Almost surely, 2^669876521 is an apocalyptic number.

It is an amenable number.

669876521 is a deficient number, since it is larger than the sum of its proper divisors (35256679).

669876521 is a wasteful number, since it uses less digits than its factorization.

669876521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35256678.

The product of its digits is 1088640, while the sum is 50.

The square root of 669876521 is about 25881.9728962071. The cubic root of 669876521 is about 874.9802535952.

The spelling of 669876521 in words is "six hundred sixty-nine million, eight hundred seventy-six thousand, five hundred twenty-one".