### Properties of the number 1121:

1121 = 19 × 59 is semiprime and squarefree.1121 has 2 distinct prime factors, 4 divisors, 9 antidivisors and 1044 totatives.

1121 has a prime digit sum 5 in base 10.

1121 has a Fibonacci digit sum 5 in base 10.

1121 has a prime digit product 2 in base 10.

1121 has a Fibonacci digit product 2 in base 10.

1121 has an oblong digit product 2 in base 10.

Reversing the decimal digits of 1121 results in an emirpimes.

1121 = 561

^{2}- 560

^{2}= 39

^{2}- 20

^{2}is the difference of 2 nonnegative squares in 2 ways.

1121 is the difference of 2 positive pentagonal numbers in 1 way.

1121 = 4

^{2}+ 9

^{2}+ 32

^{2}is the sum of 3 positive squares.

1121

^{2}is the sum of 3 positive squares.

1121 is a divisor of 1063

^{2}- 1.

1121 is an emirpimes in (at least) the following bases: 2, 3, 4, 5, 8, 9, 10, 11, 12, 14, 26, 29, 34, 37, 39, 43, 44, 47, 51, 52, 53, 54, 65, 66, 69, 70, 71, 75, 79, 80, 84, 87, 91, 94, 95, and 97.

1121 is palindromic in (at least) the following bases: 28, 32, 58, -3, -11, -35, -40, -56, -70, and -80.

1121 in base 3 = 1112112 and consists of only the digits '1' and '2'.

1121 consists of only the digits '1' and '2'.

1121 in base 23 = 22h and consists of only the digits '2' and 'h'.

1121 in base 27 = 1ee and consists of only the digits '1' and 'e'.

1121 in base 28 = 1c1 and consists of only the digits '1' and 'c'.

1121 in base 31 = 155 and consists of only the digits '1' and '5'.

1121 in base 32 = 131 and consists of only the digits '1' and '3'.

### The number 1121 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.A001082: Generalized octagonal numbers: n*(3*n-2), n=0, +- 1, +- 2, +-3....

A007089: Numbers in base 3.

A007623: Integers written in factorial base.

A007651: Describe the previous term! (method B - initial term is 1).

A007931: Numbers that contain only 1's and 2's. Nonempty binary strings of length n in lexicographic order.

A015095: Carlitz-Riordan q-Catalan numbers (recurrence version) for q=10.

A028387: a(n) = n + (n+1)^2.

A045944: Rhombic matchstick numbers: n*(3*n+2).

A049345: n written in primorial base.

A052219: Numbers whose sum of digits is 5.

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