1291161319891 has 4 divisors (see below), whose sum is σ = 1291312855384. Its totient is φ = 1291009784400.

The previous prime is 1291161319859. The next prime is 1291161319897. The reversal of 1291161319891 is 1989131611921.

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 1291161319891 - 2⁵ = 1291161319859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1291161319897) 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, 75754965 + ... + 75772006.

It is an arithmetic number, because the mean of its divisors is an integer number (322828213846).

Almost surely, 2^{1291161319891} is an apocalyptic number.

1291161319891 is a deficient number, since it is larger than the sum of its proper divisors (151535493).

1291161319891 is an equidigital number, since it uses as much as digits as its factorization.

1291161319891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151535492.

The product of its digits is 209952, while the sum is 52.

The spelling of 1291161319891 in words is "one trillion, two hundred ninety-one billion, one hundred sixty-one million, three hundred nineteen thousand, eight hundred ninety-one".