1931142991 has 4 divisors (see below), whose sum is σ = 1931533992. Its totient is φ = 1930751992.

The previous prime is 1931142953. The next prime is 1931143037. The reversal of 1931142991 is 1992411391.

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 1931142991 - 2²⁵ = 1897588559 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1931142391) 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, 187996 + ... + 198001.

It is an arithmetic number, because the mean of its divisors is an integer number (482883498).

Almost surely, 2^1931142991 is an apocalyptic number.

1931142991 is a deficient number, since it is larger than the sum of its proper divisors (391001).

1931142991 is an equidigital number, since it uses as much as digits as its factorization.

1931142991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 391000.

The product of its digits is 17496, while the sum is 40.

The square root of 1931142991 is about 43944.7720553879. The cubic root of 1931142991 is about 1245.2928008182.

The spelling of 1931142991 in words is "one billion, nine hundred thirty-one million, one hundred forty-two thousand, nine hundred ninety-one".