1 day -> 86400 seconds
1 million -> 1 000 000 (1 with 6 zeros)
1 billion -> 1 000 000 000 (1 with 9 zeros)
1 trillion -> 1 000 000 000 000(1 with 12 zeros)

Numbers in-terms of data
1 byte = 8 bits
1kb = 1000 bytes
1mb = 1000 kb
1gb = 1000 mb
1 tb = 1000 gb
1 pb = 1000 tb

1000 = 1kb 000b = 1kb or 1000 bytes
1 000 000 = 1mb 000kb 000b = 1mb or 1000 kb
1 000 000 000 = 1gb 000mb 000kb 000b = 1gb or 1000 mb
1 000 000 000 000 = 1tb 000gb 000mb 000kb 000b = 1tb or 1000 gb
1 000 000 000 000 000 = 1pb 000tb 000gb 000mb 000kb 000 b = 1pb or 1000tb

b — bytes
kb — Kilo bytes
mb — Mega bytes
gb — Giga bytes
tb — Tera bytes
pb — Peta bytes
eb — Exa bytes (if at all needed)