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205640 = 2355397
BaseRepresentation
bin110010001101001000
3101110002022
4302031020
523040030
64224012
71514351
oct621510
9343068
10205640
11130556
129b008
13727a6
1454d28
1540de5
hex32348

205640 has 32 divisors (see below), whose sum is σ = 476280. Its totient is φ = 79872.

The previous prime is 205633. The next prime is 205651. The reversal of 205640 is 46502.

It can be written as a sum of positive squares in 4 ways, for example, as 178084 + 27556 = 422^2 + 166^2 .

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 7 ways as a sum of consecutive naturals, for example, 2072 + ... + 2168.

2205640 is an apocalyptic number.

205640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 205640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (238140).

205640 is an abundant number, since it is smaller than the sum of its proper divisors (270640).

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

205640 is a wasteful number, since it uses less digits than its factorization.

205640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161 (or 157 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 205640 is about 453.4754679142. The cubic root of 205640 is about 59.0249822385.

The spelling of 205640 in words is "two hundred five thousand, six hundred forty".

Divisors: 1 2 4 5 8 10 20 40 53 97 106 194 212 265 388 424 485 530 776 970 1060 1940 2120 3880 5141 10282 20564 25705 41128 51410 102820 205640