660820 has 48 divisors (see below), whose sum is σ = 1532160. Its totient is φ = 238464.

The previous prime is 660817. The next prime is 660833. The reversal of 660820 is 28066.

660820 = T₂₄₇ + T₂₄₈ + ... + T₂₆₆.

It is a junction number, because it is equal to n+sod(n) for n = 660791 and 660800.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14037 + ... + 14083.

It is an arithmetic number, because the mean of its divisors is an integer number (31920).

2⁶⁶⁰⁸²⁰ 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 660820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (766080).

660820 is an abundant number, since it is smaller than the sum of its proper divisors (871340).

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

660820 is a wasteful number, since it uses less digits than its factorization.

660820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112 (or 110 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 660820 is about 812.9083589188. The cubic root of 660820 is about 87.1019195745.

Adding to 660820 its reverse (28066), we get a palindrome (688886).

The spelling of 660820 in words is "six hundred sixty thousand, eight hundred twenty".