1920110990991 has 4 divisors (see below), whose sum is σ = 2560147987992. Its totient is φ = 1280073993992.

The previous prime is 1920110990977. The next prime is 1920110991061. The reversal of 1920110990991 is 1990990110291.

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 1920110990991 - 2²⁵ = 1920077436559 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1920110990921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 320018498496 + ... + 320018498501.

It is an arithmetic number, because the mean of its divisors is an integer number (640036996998).

Almost surely, 2^{1920110990991} is an apocalyptic number.

1920110990991 is a deficient number, since it is larger than the sum of its proper divisors (640036997001).

1920110990991 is an equidigital number, since it uses as much as digits as its factorization.

1920110990991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 640036997000.

The product of its (nonzero) digits is 118098, while the sum is 51.

The spelling of 1920110990991 in words is "one trillion, nine hundred twenty billion, one hundred ten million, nine hundred ninety thousand, nine hundred ninety-one".