2628

2628 = 2 x 2 x 3 x 3 x 73.

2628 is the 72nd triangular number (the sum of the first 72 positive integers). Note that its external digits, 2 and 8, form a triangular number when concatenated (A077367). It is the least triangular number divisible by the 21st prime (A112456).

2628 is 101001000100 in base 2 (binary). 2628 contains only the digits 0, 1, and 2 in bases 3, 4, and 6.

2628 is a divisor of 65⁶ - 1.

2628 has a representation as a sum of two squares (A073613): 2628 = 18² + 48².

Source: On-Line Encyclopedia of Integer Sequences