997988 has 6 divisors (see below), whose sum is σ = 1746486. Its totient is φ = 498992.

The previous prime is 997973. The next prime is 997991. The reversal of 997988 is 889799.

It can be written as a sum of positive squares in only one way, i.e., 984064 + 13924 = 992^2 + 118^2 .

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 997988.

It is an unprimeable 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 as a sum of consecutive naturals, namely, 124745 + ... + 124752.

It is an arithmetic number, because the mean of its divisors is an integer number (291081).

2⁹⁹⁷⁹⁸⁸ is an apocalyptic number.

It is an amenable number.

997988 is a deficient number, since it is larger than the sum of its proper divisors (748498).

997988 is a wasteful number, since it uses less digits than its factorization.

997988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 249501 (or 249499 counting only the distinct ones).

The product of its digits is 326592, while the sum is 50.

The square root of 997988 is about 998.9934934723. The cubic root of 997988 is about 99.9328883036.

The spelling of 997988 in words is "nine hundred ninety-seven thousand, nine hundred eighty-eight".