3631 is a prime number.
3631 is 11222111 in base 3. It is 1121 in base 15.
3631 is a divisor of 4822 - 1.
3631 is the smallest of three consecutive primes with a difference of six (A047948 and A122535): 3631, 3637, 3643.
3631 is a number n such that the square of n has the property that the sum of its digits and the product of its digits are nonzero squares (A061268).
Source: On-Line Encyclopedia of Integer Sequences