It is a happy number.
21401640 is an apocalyptic number.
1401640 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 1401640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1603440).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
1401640 is a wasteful number, since it uses less digits than its factorization.
1401640 is an odious number, because the sum of its binary digits is odd.
The square root of 1401640 is about 1183.9087802698. The cubic root of 1401640 is about 111.9125593020.
Adding to 1401640 its reverse (461041), we get a palindrome (1862681).
The spelling of 1401640 in words is "one million, four hundred one thousand, six hundred forty".