655820 has 36 divisors (see below), whose sum is σ = 1519392. Its totient is φ = 237600.

The previous prime is 655807. The next prime is 655847. The reversal of 655820 is 28556.

It is a self number, because there is not a number n which added to its sum of digits gives 655820.

It is an unprimeable 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, 2285 + ... + 2555.

2⁶⁵⁵⁸²⁰ 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 655820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (759696).

655820 is an abundant number, since it is smaller than the sum of its proper divisors (863572).

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

655820 is a wasteful number, since it uses less digits than its factorization.

655820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 302 (or 289 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 26.

The square root of 655820 is about 809.8271420495. The cubic root of 655820 is about 86.8816817662.

Subtracting from 655820 its reverse (28556), we obtain a square (627264 = 792²).

It can be divided in two parts, 65 and 5820, that added together give a palindrome (5885).

The spelling of 655820 in words is "six hundred fifty-five thousand, eight hundred twenty".