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28081 is a prime number
BaseRepresentation
bin110110110110001
31102112001
412312301
51344311
6334001
7144604
oct66661
942461
1028081
111a109
1214301
13ca21
14a33b
1584c1
hex6db1

28081 has 2 divisors, whose sum is σ = 28082. Its totient is φ = 28080.

The previous prime is 28069. The next prime is 28087. The reversal of 28081 is 18082.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21025 + 7056 = 145^2 + 84^2 .

It is a cyclic number.

It is not a de Polignac number, because 28081 - 27 = 27953 is a prime.

It is a super-2 number, since 2×280812 = 1577085122, which contains 22 as substring.

It is an Ulam number.

It is a nialpdrome in base 8 and base 13.

It is not a weakly prime, because it can be changed into another prime (28087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14040 + 14041.

It is an arithmetic number, because the mean of its divisors is an integer number (14041).

228081 is an apocalyptic number.

It is an amenable number.

28081 is a deficient number, since it is larger than the sum of its proper divisors (1).

28081 is an equidigital number, since it uses as much as digits as its factorization.

28081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 28081 is about 167.5738643106. The cubic root of 28081 is about 30.3951429221.

Subtracting from 28081 its reverse (18082), we obtain a palindrome (9999).

It can be divided in two parts, 2808 and 1, that added together give a square (2809 = 532).

The spelling of 28081 in words is "twenty-eight thousand, eighty-one".