669651 has 4 divisors (see below), whose sum is σ = 892872. Its totient is φ = 446432.

The previous prime is 669649. The next prime is 669659. The reversal of 669651 is 156966.

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

It is a cyclic number.

It is not a de Polignac number, because 669651 - 2¹ = 669649 is a prime.

It is an Ulam number.

It is a D-number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 669651.

It is not an unprimeable number, because it can be changed into a prime (669659) 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, 111606 + ... + 111611.

It is an arithmetic number, because the mean of its divisors is an integer number (223218).

2⁶⁶⁹⁶⁵¹ is an apocalyptic number.

669651 is a deficient number, since it is larger than the sum of its proper divisors (223221).

669651 is a wasteful number, since it uses less digits than its factorization.

669651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223220.

The product of its digits is 9720, while the sum is 33.

The square root of 669651 is about 818.3220637377. The cubic root of 669651 is about 87.4882052129.

It can be divided in two parts, 66965 and 1, that added together give a palindrome (66966).

The spelling of 669651 in words is "six hundred sixty-nine thousand, six hundred fifty-one".