9997999 has 4 divisors (see below), whose sum is σ = 10906920. Its totient is φ = 9089080.

The previous prime is 9997997. The next prime is 9998017.

9997999 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 9997999 - 2¹ = 9997997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9997991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 454444 + ... + 454465.

It is an arithmetic number, because the mean of its divisors is an integer number (2726730).

Almost surely, 2^9997999 is an apocalyptic number.

9997999 is a deficient number, since it is larger than the sum of its proper divisors (908921).

9997999 is a wasteful number, since it uses less digits than its factorization.

9997999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 908920.

The product of its digits is 3720087, while the sum is 61.

The square root of 9997999 is about 3161.9612584597. The cubic root of 9997999 is about 215.4290979652.

It can be divided in two parts, 999 and 7999, that added together give a palindrome (8998).

The spelling of 9997999 in words is "nine million, nine hundred ninety-seven thousand, nine hundred ninety-nine".