665550 has 96 divisors (see below), whose sum is σ = 2008800. Its totient is φ = 161280.

The previous prime is 665549. The next prime is 665557. The reversal of 665550 is 55566.

665550 is a `hidden beast` number, since 6 + 655 + 5 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 22936 + ... + 22964.

It is an arithmetic number, because the mean of its divisors is an integer number (20925).

2⁶⁶⁵⁵⁵⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1004400).

665550 is an abundant number, since it is smaller than the sum of its proper divisors (1343250).

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

665550 is a wasteful number, since it uses less digits than its factorization.

665550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67 (or 56 counting only the distinct ones).

The product of its (nonzero) digits is 4500, while the sum is 27.

The square root of 665550 is about 815.8124784532. The cubic root of 665550 is about 87.3092443063.

It can be divided in two parts, 6 and 65550, that added together give a palindrome (65556).

The spelling of 665550 in words is "six hundred sixty-five thousand, five hundred fifty".