Find the odd man out? 61, 66, 83, 121, 185

Given number series is 61, 66, 83, 121, 185

Here the given series follows a pattern that,

$6161 + 22 + 1 = 6666 + 42 + 1 = 8383 + 62 + 1 = 120 (\mathrm{not} 121)120 + 82 + 1 = 185$

Hence, the odd man in the given series is 121.