18910930191 has 4 divisors (see below), whose sum is σ = 25214573592. Its totient is φ = 12607286792.

The previous prime is 18910930187. The next prime is 18910930243. The reversal of 18910930191 is 19103901981.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18910930191 - 2² = 18910930187 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18910930121) 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 3 ways as a sum of consecutive naturals, for example, 3151821696 + ... + 3151821701.

It is an arithmetic number, because the mean of its divisors is an integer number (6303643398).

Almost surely, 2^18910930191 is an apocalyptic number.

18910930191 is a deficient number, since it is larger than the sum of its proper divisors (6303643401).

18910930191 is an equidigital number, since it uses as much as digits as its factorization.

18910930191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6303643400.

The product of its (nonzero) digits is 17496, while the sum is 42.

The spelling of 18910930191 in words is "eighteen billion, nine hundred ten million, nine hundred thirty thousand, one hundred ninety-one".