Constant byte_num::convert::POW10_U64

pub const POW10_U64: [u64; 20] = [10000000000000000000, 1000000000000000000, 100000000000000000,
 10000000000000000, 1000000000000000, 100000000000000, 10000000000000,
 1000000000000, 100000000000, 10000000000, 1000000000, 100000000, 10000000,
 1000000, 100000, 10000, 1000, 100, 10, 1]