13999999

13999999 is a natural number in the decimal system. It is the seven-digit integer immediately before 14,000,000, i.e., 14,000,000 minus 1.

The number is odd and thus not divisible by 2 or 5. Its digits sum to 49, giving a digital root of 4. In decimal notation it is formed from the digits 1, 3, followed by five 9s.

In mathematical terms, 13,999,999 does not carry any widely recognized special properties beyond its proximity to a round milestone. It is congruent to -1 modulo 10 (that is, it ends in 9) and congruent to 4 modulo 9, as reflected by its digit sum. There are no commonly cited identities or constants that prominently feature this specific value.

Use and occurrence of 13,999,999 are typically as a numerical example or data label near the seven-digit boundary. It can appear in discussions about near-miss milestones, test data, serial numbering, or as a placeholder value in demonstrations where a large, non-round seven-digit number is desired. As with many large integers, its significance tends to be contextual rather than intrinsic.