It is a tau number, because it is divible by the number of its divisors (128).
It is a nialpdrome in base 6.
It is a congruent number.
21399680 is an apocalyptic number.
1399680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 1399680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2509200).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
1399680 is an frugal number, since it uses more digits than its factorization.
1399680 is an odious number, because the sum of its binary digits is odd.
The square root of 1399680 is about 1183.0807242112. The cubic root of 1399680 is about 111.8603702143.
Adding to 1399680 its product of nonzero digits (11664), we get a square (1411344 = 11882).
1399680 divided by its product of nonzero digits (11664) gives a triangular number (120 = T15).
The spelling of 1399680 in words is "one million, three hundred ninety-nine thousand, six hundred eighty".