What is both possible and impossible at the same time?

Find the next number in the series below

21 32 54 87 131 ?

What are the 50th, 63rd and 100th numbers in the sequence below?
4, 5, 8, 8, 9, 9, 12, 13, 13, 13, 17, 18, ...

A man dies of old age on his 25 birthday. How is this possible?

There were two grandmothers and their two granddaughters.
There were two husbands and their two wives.
There were two fathers and their two daughters.
There were two mothers and their two sons.
There were two maidens and their two mothers.
There were two sisters and their two brothers.
Yet there are only six, who are buried here,
All are born legitimate and relationships clear.
How can this happen?

Decode below rebus
D
N
A
T
S , D

Which word is least like the others? Third, fourth, fifth, sixth, seventh, eighth, ninth?

I travel all around the world but always stay in the corner. What am I?

Three ants are sitting at the three corners of an equilateral triangle. Each ant starts randomly picks a direction and starts to move along the edge of the triangle. What is the probability that none of the ants collide?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?