It is a tau number, because it is divible by the number of its divisors (240).
It is a nialpdrome in base 6.
It is a zygodrome in base 6.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 997920.
It is an unprimeable number.
997920 is an untouchable number, because it is not equal to the sum of proper divisors of any number.
2997920 is an apocalyptic number.
997920 is a gapful number since it is divisible by the number (90) 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 997920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2195424).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
997920 is a wasteful number, since it uses less digits than its factorization.
997920 is an odious number, because the sum of its binary digits is odd.
The square root of 997920 is about 998.9594586368. The cubic root of 997920 is about 99.9306185399.
The spelling of 997920 in words is "nine hundred ninety-seven thousand, nine hundred twenty".