We can format our number literals in NASM as follows:
291 ; decimal
0291 ; decimal - the leading 0 does not make it octal
0291d ; decimal - d suffix
0d291 ; decimal - 0d prefix
04bh ; hex - h suffix, and the leading 0 is required
0x4b ; hex - 0x prefix
0h4b ; hex - 0h prefix
725q ; octal - q suffix
0q725 ; octal - 0q prefix
10010111b ; binary - b suffix
0b1001_0111 ; binary - 0b prefix (we can use underscores!)