669761 has 4 divisors (see below), whose sum is σ = 682452. Its totient is φ = 657072.

The previous prime is 669733. The next prime is 669763. The reversal of 669761 is 167966.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 167966 = 2 ⋅83983.

It can be written as a sum of positive squares in 2 ways, for example, as 255025 + 414736 = 505^2 + 644^2 .

It is a cyclic number.

It is not a de Polignac number, because 669761 - 2¹⁰ = 668737 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 669761.

It is not an unprimeable number, because it can be changed into a prime (669763) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6266 + ... + 6371.

It is an arithmetic number, because the mean of its divisors is an integer number (170613).

2⁶⁶⁹⁷⁶¹ is an apocalyptic number.

It is an amenable number.

669761 is a deficient number, since it is larger than the sum of its proper divisors (12691).

669761 is a wasteful number, since it uses less digits than its factorization.

669761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12690.

The product of its digits is 13608, while the sum is 35.

The square root of 669761 is about 818.3892716794. The cubic root of 669761 is about 87.4929953576.

The spelling of 669761 in words is "six hundred sixty-nine thousand, seven hundred sixty-one".