820224 has 66 divisors (see below), whose sum is σ = 2394990. Its totient is φ = 270336.
The previous prime is 820223. The next prime is 820231. The reversal of 820224 is 422028.
It can be written as a sum of positive squares in only one way, i.e., 589824 + 230400 = 768^2 + 480^2 .
It is a Harshad number since it is a multiple of its sum of digits (18).
It is a d-powerful number, because it can be written as 83 + 29 + 215 + 0 + 219 + 49 .
It is a nialpdrome in base 16.
It is a junction number, because it is equal to n+sod(n) for n = 820197 and 820206.
It is not an unprimeable number, because it can be changed into a prime (820223) by changing a digit.
It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9172 + ... + 9260.
2820224 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 820224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1197495).
820224 is an abundant number, since it is smaller than the sum of its proper divisors (1574766).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
820224 is a wasteful number, since it uses less digits than its factorization.
820224 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 115 (or 94 counting only the distinct ones).
The product of its (nonzero) digits is 256, while the sum is 18.
The square root of 820224 is about 905.6621886774. The cubic root of 820224 is about 93.6075382927.
The spelling of 820224 in words is "eight hundred twenty thousand, two hundred twenty-four".
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