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20810 = 252081
BaseRepresentation
bin101000101001010
31001112202
411011022
51131220
6240202
7114446
oct50512
931482
1020810
11146a9
1210062
13961a
147826
156275
hex514a

20810 has 8 divisors (see below), whose sum is σ = 37476. Its totient is φ = 8320.

The previous prime is 20809. The next prime is 20849. The reversal of 20810 is 1802.

20810 = T45 + T46 + ... + T59.

20810 = 362 + 372 + ... + 472.

It can be written as a sum of positive squares in 2 ways, for example, as 20449 + 361 = 143^2 + 19^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×208102 = 866112200, which contains 22 as substring.

It is a Curzon number.

It is a plaindrome in base 7.

It is a junction number, because it is equal to n+sod(n) for n = 20791 and 20800.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1031 + ... + 1050.

220810 is an apocalyptic number.

20810 is a deficient number, since it is larger than the sum of its proper divisors (16666).

20810 is a wasteful number, since it uses less digits than its factorization.

20810 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2088.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 20810 is about 144.2567156149. The cubic root of 20810 is about 27.5057839074.

The spelling of 20810 in words is "twenty thousand, eight hundred ten".

Divisors: 1 2 5 10 2081 4162 10405 20810