9990999 has 32 divisors (see below), whose sum is σ = 15522240. Its totient is φ = 6345216.

The previous prime is 9990997. The next prime is 9991027.

9990999 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 9990999 - 2¹ = 9990997 is a prime.

It is a super-2 number, since 2×9990999² = 199640122036002, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9990997) 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 31 ways as a sum of consecutive naturals, for example, 72859 + ... + 72995.

It is an arithmetic number, because the mean of its divisors is an integer number (485070).

Almost surely, 2^9990999 is an apocalyptic number.

9990999 is a deficient number, since it is larger than the sum of its proper divisors (5531241).

9990999 is a wasteful number, since it uses less digits than its factorization.

9990999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 256 (or 250 counting only the distinct ones).

The product of its (nonzero) digits is 531441, while the sum is 54.

The square root of 9990999 is about 3160.8541567114. The cubic root of 9990999 is about 215.3788093771.

The spelling of 9990999 in words is "nine million, nine hundred ninety thousand, nine hundred ninety-nine".