997728 has 48 divisors (see below), whose sum is σ = 2761920. Its totient is φ = 314496.

The previous prime is 997727. The next prime is 997739. The reversal of 997728 is 827799.

997728 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (48).

It is a super-2 number, since 2×997728² = 1990922323968, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 997728.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1551 + ... + 2097.

It is an arithmetic number, because the mean of its divisors is an integer number (57540).

2⁹⁹⁷⁷²⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 997728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1380960).

997728 is an abundant number, since it is smaller than the sum of its proper divisors (1764192).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

997728 is a wasteful number, since it uses less digits than its factorization.

997728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 579 (or 571 counting only the distinct ones).

The product of its digits is 63504, while the sum is 42.

The square root of 997728 is about 998.8633540180. The cubic root of 997728 is about 99.9242092388.

The spelling of 997728 in words is "nine hundred ninety-seven thousand, seven hundred twenty-eight".