610

610 = 2 x 5 x 61.

610 is the 15th Fibonacci number (A000045). It is the smallest Fibonacci number that begins with 6.

610 is 747 in base 9 and 505 in base 11.

610 is the sum of the squares of the divisors of 22 (A001157): 610 = 1² + 2² + 11² + 22².

610 is the number of primes less than 4500 (A028505).

610 is a Markov number.

610 has two representations as a sum of two squares: 610 = 9² + 23² = 13² + 21².

610 is a divisor of 11⁴ - 1.

Source: Number Gossip