191211121121 has 16 divisors (see below), whose sum is σ = 197983170000. Its totient is φ = 184544870400.

The previous prime is 191211121109. The next prime is 191211121141. The reversal of 191211121121 is 121121112191.

It can be written as a sum of positive squares in 8 ways, for example, as 2876820496 + 188334300625 = 53636^2 + 433975^2 .

It is a de Polignac number, because none of the positive numbers 2^k-191211121121 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (191211121141) 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, 2831255 + ... + 2898003.

It is an arithmetic number, because the mean of its divisors is an integer number (12373948125).

Almost surely, 2^191211121121 is an apocalyptic number.

It is an amenable number.

191211121121 is a deficient number, since it is larger than the sum of its proper divisors (6772048879).

191211121121 is a wasteful number, since it uses less digits than its factorization.

191211121121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67540.

The product of its digits is 72, while the sum is 23.

The spelling of 191211121121 in words is "one hundred ninety-one billion, two hundred eleven million, one hundred twenty-one thousand, one hundred twenty-one".