Ans: A Sunday.

1 ordinary year = 365 days = (52 weeks + 1 day.)

1 ordinary year has 1 odd day.

1 leap year = 366 days = (52 weeks + 2 days)

Number of odd days in 400 years = (5 x 4 + 1) 0 odd day.

As per above formula we need to calculate odd days.

We shoudl understand any year divisible by 400 will have odd days 0

If we take 542695283217 = 542695283200 + 17

As per divisibility rule for 4 (last two digits should be divisible by 4) above number is divisible by 400 and hence it will have 0 odd days.

for 17 years 16 complete years + 5 months 25 days

i.e 4 leap years + 12 normal years + (31 + 28 + 31 + 30 + 31 + 25) days

i.e 4 * 2 + 12 + 176 odd days

i.e 196 odd days = 28 weeks + 0 odd days = 0 odd days, hence it is Sunday.