191310312109 has 4 divisors (see below), whose sum is σ = 218640356704. Its totient is φ = 163980267516.

The previous prime is 191310312103. The next prime is 191310312163. The reversal of 191310312109 is 901213013191.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 901213013191 = 199 ⋅4528708609.

It is a cyclic number.

It is not a de Polignac number, because 191310312109 - 2¹⁹ = 191309787821 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191310312103) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13665022287 + ... + 13665022300.

It is an arithmetic number, because the mean of its divisors is an integer number (54660089176).

Almost surely, 2^191310312109 is an apocalyptic number.

It is an amenable number.

191310312109 is a deficient number, since it is larger than the sum of its proper divisors (27330044595).

191310312109 is an equidigital number, since it uses as much as digits as its factorization.

191310312109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27330044594.

The product of its (nonzero) digits is 1458, while the sum is 31.

The spelling of 191310312109 in words is "one hundred ninety-one billion, three hundred ten million, three hundred twelve thousand, one hundred nine".