669686669 has 4 divisors (see below), whose sum is σ = 670335996. Its totient is φ = 669037344.

The previous prime is 669686663. The next prime is 669686681. The reversal of 669686669 is 966686966.

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

It can be written as a sum of positive squares in 2 ways, for example, as 408444100 + 261242569 = 20210^2 + 16163^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-669686669 is a prime.

It is a super-3 number, since 3×669686669³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669686663) 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, 323114 + ... + 325179.

It is an arithmetic number, because the mean of its divisors is an integer number (167583999).

Almost surely, 2^669686669 is an apocalyptic number.

It is an amenable number.

669686669 is a deficient number, since it is larger than the sum of its proper divisors (649327).

669686669 is a wasteful number, since it uses less digits than its factorization.

669686669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 649326.

The product of its digits is 30233088, while the sum is 62.

The square root of 669686669 is about 25878.3049869963. The cubic root of 669686669 is about 874.8975854011.

It can be divided in two parts, 66968 and 6669, that added together give a palindrome (73637).

The spelling of 669686669 in words is "six hundred sixty-nine million, six hundred eighty-six thousand, six hundred sixty-nine".