9965999 has 4 divisors (see below), whose sum is σ = 9972336. Its totient is φ = 9959664.

The previous prime is 9965959. The next prime is 9966001. The reversal of 9965999 is 9995699.

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: 9995699 = 7 ⋅1427957.

It is a cyclic number.

It is not a de Polignac number, because 9965999 - 2⁸ = 9965743 is a prime.

It is a super-2 number, since 2×9965999² = 198642272136002, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9965959) by changing a digit.

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, 1187 + ... + 4619.

It is an arithmetic number, because the mean of its divisors is an integer number (2493084).

Almost surely, 2^9965999 is an apocalyptic number.

9965999 is a deficient number, since it is larger than the sum of its proper divisors (6337).

9965999 is a wasteful number, since it uses less digits than its factorization.

9965999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6336.

The product of its digits is 1771470, while the sum is 56.

The square root of 9965999 is about 3156.8970524868. The cubic root of 9965999 is about 215.1990152915.

The spelling of 9965999 in words is "nine million, nine hundred sixty-five thousand, nine hundred ninety-nine".