144

is the integer between.

Math features

 * 144 is an even number.
 * 144 is also known a gross, being 122.
 * 144 is an abundant number, like all multiples of 6; therefore, 144 is also a composite number.
 * 144 is a dozen dozen.
 * 144 is a Harshad number.
 * 144 is a sum-product number. It is the last, after 0, 1 and 135.

Palindrome also a square
See also: Palindromic square numbers (121 and 676) and Square with palindrome also square (all)

144 is one of seven 3-digit numbers which palindrome is also a  square number. These are: { 1 ,  100 }, { 4, 400 }, { 9 , 900 }, { 121 , 121 }, { 144 , 441 }, { 676 , 676 } and { 169 , 961 }.

There are four-digit variants, like 1089 and 9801.