997399999 has 4 divisors (see below), whose sum is σ = 997488936. Its totient is φ = 997311064.

The previous prime is 997399981. The next prime is 997400011. The reversal of 997399999 is 999993799.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 999993799 = 7 ⋅142856257.

It is a cyclic number.

It is not a de Polignac number, because 997399999 - 2¹⁷ = 997268927 is a prime.

It is a Duffinian number.

997399999 is a modest number, since divided by 99999 gives 9973 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997399939) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24724 + ... + 51049.

It is an arithmetic number, because the mean of its divisors is an integer number (249372234).

Almost surely, 2^997399999 is an apocalyptic number.

997399999 is a deficient number, since it is larger than the sum of its proper divisors (88937).

997399999 is a wasteful number, since it uses less digits than its factorization.

997399999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88936.

The product of its digits is 100442349, while the sum is 73.

The square root of 997399999 is about 31581.6402202292. The cubic root of 997399999 is about 999.1325808015.

The spelling of 997399999 in words is "nine hundred ninety-seven million, three hundred ninety-nine thousand, nine hundred ninety-nine".