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BaseRepresentation
bin10100000001
31202110
4110001
520111
65533
73510
oct2401
91673
101281
11a65
128a9
13777
14677
155a6
hex501

1281 has 8 divisors (see below), whose sum is σ = 1984. Its totient is φ = 720.

The previous prime is 1279. The next prime is 1283. The reversal of 1281 is 1821.

It can be divided in two parts, 1 and 281, that added together give a palindrome (282).

It is a happy number.

1281 is nontrivially palindromic in base 13.

It is an interprime number because it is at equal distance from previous prime (1279) and next prime (1283).

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

It is not a de Polignac number, because 1281 - 21 = 1279 is a prime.

It is a super-2 number, since 2×12812 = 3281922, which contains 22 as substring.

It is a Duffinian number.

1281 is a lucky number.

1281 is a nontrivial repdigit in base 13.

It is a plaindrome in base 13 and base 14.

It is a nialpdrome in base 6, base 11 and base 13.

It is a zygodrome in base 6 and base 13.

It is not an unprimeable number, because it can be changed into a prime (1283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (3) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10 + ... + 51.

It is an arithmetic number, because the mean of its divisors is an integer number (248).

It is a Proth number, since it is equal to 5 ⋅ 28 + 1 and 5 < 28.

21281 is an apocalyptic number.

1281 is the 21-st octagonal number.

It is an amenable number.

1281 is a deficient number, since it is larger than the sum of its proper divisors (703).

1281 is an equidigital number, since it uses as much as digits as its factorization.

1281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71.

The product of its digits is 16, while the sum is 12.

The square root of 1281 is about 35.7910603363. The cubic root of 1281 is about 10.8604972487.

The spelling of 1281 in words is "one thousand, two hundred eighty-one".

Divisors: 1 3 7 21 61 183 427 1281