660880 has 40 divisors (see below), whose sum is σ = 1678464. Its totient is φ = 240000.

The previous prime is 660853. The next prime is 660887. The reversal of 660880 is 88066.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Smith number, since the sum of its digits (28) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (660887) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 505 + ... + 1255.

2⁶⁶⁰⁸⁸⁰ 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 660880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (839232).

660880 is an abundant number, since it is smaller than the sum of its proper divisors (1017584).

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

660880 is a wasteful number, since it uses less digits than its factorization.

660880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 775 (or 769 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 660880 is about 812.9452626100. The cubic root of 660880 is about 87.1045556716.

It can be divided in two parts, 660 and 880, that added together give a triangular number (1540 = T₅₅).

The spelling of 660880 in words is "six hundred sixty thousand, eight hundred eighty".