• 145 can be written using four 4's:
145 is nontrivially palindromic in base 9 and base 12.
145 is an esthetic number in base 3, base 4, base 12 and base 15, because in such bases its adjacent digits differ by 1.
It is a semiprime because it is the product of two primes.
It is a cyclic number.
It is a Leyland number of the form 43 + 34.
It is an Ulam number.
It is an alternating number because its digits alternate between odd and even.
145 is an undulating number in base 9 and base 12.
It is a plaindrome in base 10, base 11 and base 15.
It is a nialpdrome in base 8, base 13, base 14 and base 16.
It is a congruent number.
145 is the 10-th pentagonal number.
145 is the 9-th centered square number.
It is an amenable number.
145 is an equidigital number, since it uses as much as digits as its factorization.
145 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 34.
The square root of 145 is about 12.0415945788. The cubic root of 145 is about 5.2535878725.
Subtracting from 145 its product of digits (20), we obtain a cube (125 = 53).
Adding to 145 its reverse (541), we get a palindrome (686).
The spelling of 145 in words is "one hundred forty-five", and thus it is an aban number.