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220820 = 22561181
BaseRepresentation
bin110101111010010100
3102012220112
4311322110
524031240
64422152
71606535
oct657224
9365815
10220820
111409a6
12a7958
1379682
145a68c
1545665
hex35e94

220820 has 24 divisors (see below), whose sum is σ = 473928. Its totient is φ = 86400.

The previous prime is 220811. The next prime is 220841. The reversal of 220820 is 28022.

It can be written as a sum of positive squares in 4 ways, for example, as 21904 + 198916 = 148^2 + 446^2 .

It is a super-2 number, since 2×2208202 = 97522944800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 220795 and 220804.

It is a congruent number.

It is an unprimeable number.

220820 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1130 + ... + 1310.

It is an arithmetic number, because the mean of its divisors is an integer number (19747).

2220820 is an apocalyptic number.

220820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

220820 is an abundant number, since it is smaller than the sum of its proper divisors (253108).

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

220820 is a wasteful number, since it uses less digits than its factorization.

220820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251 (or 249 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 220820 is about 469.9148859102. The cubic root of 220820 is about 60.4430171752.

Adding to 220820 its reverse (28022), we get a palindrome (248842).

The spelling of 220820 in words is "two hundred twenty thousand, eight hundred twenty".

Divisors: 1 2 4 5 10 20 61 122 181 244 305 362 610 724 905 1220 1810 3620 11041 22082 44164 55205 110410 220820