191026109489 has 4 divisors (see below), whose sum is σ = 191043885156. Its totient is φ = 191008333824.

The previous prime is 191026109479. The next prime is 191026109513. The reversal of 191026109489 is 984901620191.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 984901620191 = 17 ⋅57935389423.

It can be written as a sum of positive squares in 2 ways, for example, as 169585828864 + 21440280625 = 411808^2 + 146425^2 .

It is a cyclic number.

It is not a de Polignac number, because 191026109489 - 2¹⁶ = 191026043953 is a prime.

It is a super-2 number, since 2×191026109489² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (191026109479) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8871704 + ... + 8893209.

It is an arithmetic number, because the mean of its divisors is an integer number (47760971289).

Almost surely, 2^191026109489 is an apocalyptic number.

It is an amenable number.

191026109489 is a deficient number, since it is larger than the sum of its proper divisors (17775667).

191026109489 is a wasteful number, since it uses less digits than its factorization.

191026109489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17775666.

The product of its (nonzero) digits is 279936, while the sum is 50.

The spelling of 191026109489 in words is "one hundred ninety-one billion, twenty-six million, one hundred nine thousand, four hundred eighty-nine".