666544 has 10 divisors (see below), whose sum is σ = 1291460. Its totient is φ = 333264.

The previous prime is 666541. The next prime is 666557. The reversal of 666544 is 445666.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (666541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20814 + ... + 20845.

It is an arithmetic number, because the mean of its divisors is an integer number (129146).

2⁶⁶⁶⁵⁴⁴ is an apocalyptic number.

It is an amenable number.

666544 is a deficient number, since it is larger than the sum of its proper divisors (624916).

666544 is a wasteful number, since it uses less digits than its factorization.

666544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41667 (or 41661 counting only the distinct ones).

The product of its digits is 17280, while the sum is 31.

The square root of 666544 is about 816.4214597865. The cubic root of 666544 is about 87.3526881848.

The spelling of 666544 in words is "six hundred sixty-six thousand, five hundred forty-four".