669845 has 16 divisors (see below), whose sum is σ = 924480. Its totient is φ = 460800.

The previous prime is 669839. The next prime is 669847. The reversal of 669845 is 548966.

It is not a de Polignac number, because 669845 - 2¹⁰ = 668821 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 669799 and 669808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669847) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 725 + ... + 1365.

It is an arithmetic number, because the mean of its divisors is an integer number (57780).

2⁶⁶⁹⁸⁴⁵ is an apocalyptic number.

It is an amenable number.

669845 is a deficient number, since it is larger than the sum of its proper divisors (254635).

669845 is a wasteful number, since it uses less digits than its factorization.

669845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 676.

The product of its digits is 51840, while the sum is 38.

The square root of 669845 is about 818.4405903913. The cubic root of 669845 is about 87.4966529332.

It can be divided in two parts, 6 and 69845, that multiplied together give a triangular number (419070 = T₉₁₅).

The spelling of 669845 in words is "six hundred sixty-nine thousand, eight hundred forty-five".