660816 has 60 divisors (see below), whose sum is σ = 1997268. Its totient is φ = 202752.

The previous prime is 660811. The next prime is 660817. The reversal of 660816 is 618066.

660816 is nontrivially palindromic in base 5.

It can be written as a sum of positive squares in 2 ways, for example, as 176400 + 484416 = 420^2 + 696^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 660816.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660811) by changing a digit.

660816 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 11 ways as a sum of consecutive naturals, for example, 1696 + ... + 2048.

2⁶⁶⁰⁸¹⁶ 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 660816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (998634).

660816 is an abundant number, since it is smaller than the sum of its proper divisors (1336452).

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

660816 is a wasteful number, since it uses less digits than its factorization.

660816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 380 (or 371 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 660816 is about 812.9058986131. The cubic root of 660816 is about 87.1017438290.

The spelling of 660816 in words is "six hundred sixty thousand, eight hundred sixteen".