1145 has 4 divisors (see below), whose sum is σ = 1380.
Its totient is φ = 912.
The previous prime is 1129. The next prime is 1151. The reversal of 1145 is 5411.
Adding to 1145 its sum of digits (11), we get a square (1156 = 342).
Adding to 1145 its reverse (5411), we get a palindrome (6556).
1145 is nontrivially palindromic in base 15.
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5411 = 7 ⋅773.
It can be written as a sum of positive squares in 2 ways, for example, as 784 + 361 = 28^2 + 19^2
It is a cyclic number.
It is not a de Polignac number, because 1145 - 24 = 1129 is a prime.
It is a super-2 number, since 2×11452 = 2622050, which contains 22 as substring.
1145 is an undulating number in base 15.
It is a plaindrome in base 10, base 14 and base 16.
It is a nialpdrome in base 11.
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, 110 + ... + 119.
It is an arithmetic number, because the mean of its divisors is an integer number (345).
It is an amenable number.
1145 is a deficient number, since it is larger than the sum of its proper divisors (235).
1145 is an equidigital number, since it uses as much as digits as its factorization.
1145 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 234.
The product of its digits is 20, while the sum is 11.
The square root of 1145 is about 33.8378486314.
The cubic root of 1145 is about 10.4616895662.
The spelling of 1145 in words is "one thousand, one hundred forty-five".