No.
23456 + 654321 = 677,777
1/1 or any number that is the exact same one the top of the fraction (Numerator) as it is in the bottom of the fraction (denominator) like 1/1 or 654321/654321
0 or if it's a trick question about the years going back, 1BC
Not sure about a square route, but the square root of 654321 is 808.901 (to 3 dp).
odd
No, Phone number in the UK have an area code, followed by a loacl number. The Area Code always starts with a '0' (that is how the equipment distinguishes an area code from a local number). For example: 020-8765 4321 ('020' is the area code for London. London has 8-figure numbers. From inside London you only need to dial: 8765 4321). 01632-654321 ('01632' is the area code here, '654321' is the local number). 7700074589 is too long for a local number, and doesn't start with a '0' so cannot include the area code. 0770 007 4589 may be a valid number, but this is unlikely as local numbers do not normally start with '0'. The country code for the UK is '44', so the second number can also be quoted as: +44 1632 654321 or: 0044 1632 654321
720
654321
654321-100000= 554321 combinations
You is called a prime number!You is called a prime number!You is called a prime number!You is called a prime number!
7 is a prime number!
109 is a prime number.