Solution:
Grouping the elements of the product by ten we get:
(30k+1)(30k+4)(30k+7)(30k+10)(30k+13)(30k+16)(30k+19)(30k+22)(30k+25)(30k+28)==(30k+1)(15k+2)(30k+7)(120k+40)(30k+13)(15k+8)(30k+19)(15k+11)(120k+100)(15k+14)
(We divide all even numbers not divisible by five, by two and multiply all numbers divisible by five with four.)
We denote Pk=(30k+1)(15k+2)(30k+7)(30k+13)(15k+8)(30k+19)(15k+11)(15k+14). For all the numbers not divisible by five, only the last digit affects the solution, since the power of two in the numbers divisible by five is greater than the power of five. Considering this, for even k, Pk ends with the same digit as 1⋅2⋅7⋅3⋅8⋅9⋅1⋅4, i.e. six and for odd k, Pk ends with the same digit as 1⋅7⋅7⋅3⋅3⋅9⋅6⋅9, i.e. six. Thus P0P1…P66 ends with six. If we remove one zero from the end of all numbers divisible with five, we get that the last nonzero digit of the given product is the same as the one from 6⋅2011⋅2014⋅4⋅10⋅16⋅…⋅796⋅802. Considering that 4⋅6⋅2⋅8 ends with four and removing one zero from every fifth number we get that the last nonzero digit is the same as in 4⋅426⋅784⋅796⋅802⋅1⋅4⋅…⋅76⋅79. Repeating the process we did for the starting sequence we conclude that the last nonzero number will be the same as in 2⋅6⋅6⋅40⋅100⋅160⋅220⋅280⋅61⋅32⋅67⋅73⋅38⋅79, which is two.