669432821 has 8 divisors (see below), whose sum is σ = 683201760. Its totient is φ = 655744752.

The previous prime is 669432791. The next prime is 669432847. The reversal of 669432821 is 128234966.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-669432821 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669032821) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3350 + ... + 36743.

It is an arithmetic number, because the mean of its divisors is an integer number (85400220).

Almost surely, 2^669432821 is an apocalyptic number.

It is an amenable number.

669432821 is a deficient number, since it is larger than the sum of its proper divisors (13768939).

669432821 is a wasteful number, since it uses less digits than its factorization.

669432821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40435.

The product of its digits is 124416, while the sum is 41.

The square root of 669432821 is about 25873.3998732289. The cubic root of 669432821 is about 874.7870266975.

The spelling of 669432821 in words is "six hundred sixty-nine million, four hundred thirty-two thousand, eight hundred twenty-one".