What is 1000000000000000000000 10000000000000000000000000000000000000000000000000000000000000?

The expression you provided appears to be a concatenation of two very large numbers: 1 followed by 21 zeros (1 sextillion) and 1 followed by 48 zeros (1 quindecillion). If you meant to perform an operation between them, please specify, as currently, it's simply a representation of two distinct large values.