669890 has 16 divisors (see below), whose sum is σ = 1298808. Its totient is φ = 247296.

The previous prime is 669887. The next prime is 669901. The reversal of 669890 is 98966.

It can be written as a sum of positive squares in 4 ways, for example, as 461041 + 208849 = 679^2 + 457^2 .

It is a super-2 number, since 2×669890² = 897505224200, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2447 + ... + 2706.

2⁶⁶⁹⁸⁹⁰ is an apocalyptic number.

669890 is a deficient number, since it is larger than the sum of its proper divisors (628918).

669890 is a wasteful number, since it uses less digits than its factorization.

669890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5173.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 669890 is about 818.4680812347. The cubic root of 669890 is about 87.4986122229.

It can be divided in two parts, 6 and 69890, that added together give a palindrome (69896).

The spelling of 669890 in words is "six hundred sixty-nine thousand, eight hundred ninety".