17991116121 has 16 divisors (see below), whose sum is σ = 26400484800. Its totient is φ = 10807211520.

The previous prime is 17991116111. The next prime is 17991116123. The reversal of 17991116121 is 12161119971.

It is not a de Polignac number, because 17991116121 - 2⁷ = 17991115993 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 17991116121.

It is not an unprimeable number, because it can be changed into a prime (17991116123) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2408596 + ... + 2416053.

It is an arithmetic number, because the mean of its divisors is an integer number (1650030300).

Almost surely, 2^17991116121 is an apocalyptic number.

17991116121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

17991116121 is a deficient number, since it is larger than the sum of its proper divisors (8409368679).

17991116121 is a wasteful number, since it uses less digits than its factorization.

17991116121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4824776.

The product of its digits is 6804, while the sum is 39.

The spelling of 17991116121 in words is "seventeen billion, nine hundred ninety-one million, one hundred sixteen thousand, one hundred twenty-one".