Search a number
1081 = 2347

1081 has 4 divisors (see below), whose sum is σ = 1152. Its totient is φ = 1012.

The previous prime is 1069. The next prime is 1087. The reversal of 1081 is 1801.

1081 is a nontrivial binomial coefficient, being equal to C(47, 2).

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 1081 - 25 = 1049 is a prime.

It is a super-2 number, since 2×10812 = 2337122, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a nialpdrome in base 12 and base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1 + ... + 46.

It is an arithmetic number, because the mean of its divisors is an integer number (288).

21081 is an apocalyptic number.

1081 is the 46-th triangular number.

1081 is the 16-th centered nonagonal number.

It is an amenable number.

1081 is a deficient number, since it is larger than the sum of its proper divisors (71).

1081 is an equidigital number, since it uses as much as digits as its factorization.

1081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70.

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 1081 is about 32.8785644455. The cubic root of 1081 is about 10.2630213253.

Adding to 1081 its reverse (1801), we get a palindrome (2882).

It can be divided in two parts, 10 and 81, that added together give a triangular number (91 = T13).

The spelling of 1081 in words is "one thousand, eighty-one".

Divisors: 1 23 47 1081