991199009911 has 8 divisors (see below), whose sum is σ = 1081629964800. Its totient is φ = 900821714040.

The previous prime is 991199009837. The next prime is 991199009951. The reversal of 991199009911 is 119900991199.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991199009911 is a prime.

It is a zygodrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991199009951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13376121 + ... + 13450018.

It is an arithmetic number, because the mean of its divisors is an integer number (135203745600).

Almost surely, 2^991199009911 is an apocalyptic number.

991199009911 is a deficient number, since it is larger than the sum of its proper divisors (90430954889).

991199009911 is a wasteful number, since it uses less digits than its factorization.

991199009911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26829509.

The product of its (nonzero) digits is 531441, while the sum is 58.

The spelling of 991199009911 in words is "nine hundred ninety-one billion, one hundred ninety-nine million, nine thousand, nine hundred eleven".