666441 has 8 divisors (see below), whose sum is σ = 987360. Its totient is φ = 444276.

The previous prime is 666439. The next prime is 666461. The reversal of 666441 is 144666.

It is not a de Polignac number, because 666441 - 2¹ = 666439 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 24683 = 666441 / (6 + 6 + 6 + 4 + 4 + 1).

It is a nialpdrome in base 10.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 666441.

It is not an unprimeable number, because it can be changed into a prime (666431) 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, 12315 + ... + 12368.

It is an arithmetic number, because the mean of its divisors is an integer number (123420).

2⁶⁶⁶⁴⁴¹ is an apocalyptic number.

It is an amenable number.

666441 is a deficient number, since it is larger than the sum of its proper divisors (320919).

666441 is a wasteful number, since it uses less digits than its factorization.

666441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24692 (or 24686 counting only the distinct ones).

The product of its digits is 3456, while the sum is 27.

The square root of 666441 is about 816.3583771849. The cubic root of 666441 is about 87.3481884617.

The spelling of 666441 in words is "six hundred sixty-six thousand, four hundred forty-one".