669423809 has 4 divisors (see below), whose sum is σ = 698529216. Its totient is φ = 640318404.

The previous prime is 669423803. The next prime is 669423817. The reversal of 669423809 is 908324966.

669423809 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 669423809 - 2⁴ = 669423793 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (669423803) 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, 14552669 + ... + 14552714.

It is an arithmetic number, because the mean of its divisors is an integer number (174632304).

Almost surely, 2^669423809 is an apocalyptic number.

It is an amenable number.

669423809 is a deficient number, since it is larger than the sum of its proper divisors (29105407).

669423809 is a wasteful number, since it uses less digits than its factorization.

669423809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29105406.

The product of its (nonzero) digits is 559872, while the sum is 47.

The square root of 669423809 is about 25873.2257169453. The cubic root of 669423809 is about 874.7831011774.

It can be divided in two parts, 6694 and 23809, that added together give a palindrome (30503).

The spelling of 669423809 in words is "six hundred sixty-nine million, four hundred twenty-three thousand, eight hundred nine".