2145 has 16 divisors (see below), whose sum is σ = 4032.
Its totient is φ = 960.
The previous prime is 2143. The next prime is 2153. The reversal of 2145 is 5412.
Adding to 2145 its reverse (5412), we get a palindrome (7557).
It can be divided in two parts, 21 and 45, that added together give a palindrome (66).
2145 = T14 + T15 + ... +
2145 is nontrivially palindromic in base 2.
2145 is a nontrivial binomial coefficient, being equal to C(66, 2).
It is not a de Polignac number, because 2145 - 21 = 2143 is a prime.
It is an alternating number because its digits alternate between even and odd.
2145 is an undulating number in base 8.
It is a nialpdrome in base 3, base 13, base 15 and base 16.
It is a self number, because there is not a number n which added to its sum of digits gives 2145.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (2141) by changing a digit.
It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 159 + ... + 171.
It is an arithmetic number, because the mean of its divisors is an integer number (252).
2145 is the 65-th triangular number and also the 33-rd hexagonal number.
It is an amenable number.
2145 is a deficient number, since it is larger than the sum of its proper divisors (1887).
2145 is a wasteful number, since it uses less digits than its factorization.
2145 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 32.
The product of its digits is 40, while the sum is 12.
The square root of 2145 is about 46.3141447076.
The cubic root of 2145 is about 12.8966159022.
The spelling of 2145 in words is "two thousand, one hundred forty-five".