660440 has 64 divisors (see below), whose sum is σ = 1728000. Its totient is φ = 224640.

The previous prime is 660409. The next prime is 660449. The reversal of 660440 is 44066.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660449) by changing a digit.

660440 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8321 + ... + 8399.

It is an arithmetic number, because the mean of its divisors is an integer number (27000).

2⁶⁶⁰⁴⁴⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 660440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (864000).

660440 is an abundant number, since it is smaller than the sum of its proper divisors (1067560).

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

660440 is a wasteful number, since it uses less digits than its factorization.

660440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120 (or 116 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 660440 is about 812.6745966252. The cubic root of 660440 is about 87.0852205864.

The spelling of 660440 in words is "six hundred sixty thousand, four hundred forty".