2016 is the natural number following 2015 and preceding 2017.
In mathematics
2016 is a triangular number, being 1 + 2 + 3 + ... + 63. Equivalently, . 2016 is a 24-gonal number and a generalized 28-gonal (icosioctagonal) number . 2016 has 36 divisors. 211 − 25 = 2016. 2016 forms a friendly pair with 360, as and . The number 360 itself is a highly composite number, while 2016, while not highly composite, is highly composite among the positive integers not divisible by five. 2016 × 2 + 1 = 4033. Although 4033 is not prime, as 4033 = 37 × 109, it is a strong pseudoprime to base 2 . Aside from 2016, the only other numbers below 10,000 with this property are 1023, 1638, 2340, 4160, and 7920. There are 2016 five-cubes in a nine-cube. 2016 is an Erdős–Nicolas number because, while not perfect, 2016 is the sum of its first 31 divisors (up to and including 288). 2016 × 20 = 40,320 = (read as "8 factorial"). is prime. Since 2017 is similarly prime, 201617 + 1 is a semiprime.