997688 has 16 divisors (see below), whose sum is σ = 1881360. Its totient is φ = 496000.

The previous prime is 997681. The next prime is 997693. The reversal of 997688 is 886799.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997681) by changing a digit.

997688 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2288 + ... + 2688.

It is an arithmetic number, because the mean of its divisors is an integer number (117585).

2⁹⁹⁷⁶⁸⁸ is an apocalyptic number.

It is an amenable number.

997688 is a deficient number, since it is larger than the sum of its proper divisors (883672).

997688 is a wasteful number, since it uses less digits than its factorization.

997688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 718 (or 714 counting only the distinct ones).

The product of its digits is 217728, while the sum is 47.

The square root of 997688 is about 998.8433310585. The cubic root of 997688 is about 99.9228738642.

Subtracting from 997688 its reverse (886799), we obtain a square (110889 = 333²).

The spelling of 997688 in words is "nine hundred ninety-seven thousand, six hundred eighty-eight".