669691 has 8 divisors (see below), whose sum is σ = 762624. Its totient is φ = 582120.

The previous prime is 669689. The next prime is 669701. The reversal of 669691 is 196966.

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

It is not a de Polignac number, because 669691 - 2¹ = 669689 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 669691.

It is not an unprimeable number, because it can be changed into a prime (669611) 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, 1071 + ... + 1576.

It is an arithmetic number, because the mean of its divisors is an integer number (95328).

2⁶⁶⁹⁶⁹¹ is an apocalyptic number.

669691 is a deficient number, since it is larger than the sum of its proper divisors (92933).

669691 is a wasteful number, since it uses less digits than its factorization.

669691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2681.

The product of its digits is 17496, while the sum is 37.

The square root of 669691 is about 818.3465036279. The cubic root of 669691 is about 87.4899471444.

The spelling of 669691 in words is "six hundred sixty-nine thousand, six hundred ninety-one".