665544 has 32 divisors (see below), whose sum is σ = 1815840. Its totient is φ = 201600.

The previous prime is 665527. The next prime is 665549. The reversal of 665544 is 445566.

It is a plaindrome in base 14.

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (665549) by changing a digit.

665544 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is an upside-down number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 997 + ... + 1524.

It is an arithmetic number, because the mean of its divisors is an integer number (56745).

2⁶⁶⁵⁵⁴⁴ is an apocalyptic number.

It is an amenable number.

665544 is an abundant number, since it is smaller than the sum of its proper divisors (1150296).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

665544 is a wasteful number, since it uses less digits than its factorization.

665544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2541 (or 2537 counting only the distinct ones).

The product of its digits is 14400, while the sum is 30.

The square root of 665544 is about 815.8088011293. The cubic root of 665544 is about 87.3089819383.

The spelling of 665544 in words is "six hundred sixty-five thousand, five hundred forty-four".