1991291411 has 4 divisors (see below), whose sum is σ = 1991623272. Its totient is φ = 1990959552.

The previous prime is 1991291399. The next prime is 1991291513. The reversal of 1991291411 is 1141921991.

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 1991291411 - 2¹⁰ = 1991290387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1991291711) 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, 156761 + ... + 168986.

It is an arithmetic number, because the mean of its divisors is an integer number (497905818).

Almost surely, 2^1991291411 is an apocalyptic number.

1991291411 is a deficient number, since it is larger than the sum of its proper divisors (331861).

1991291411 is an equidigital number, since it uses as much as digits as its factorization.

1991291411 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 331860.

The product of its digits is 5832, while the sum is 38.

The square root of 1991291411 is about 44623.8883446972. Note that the first 3 decimals coincide. The cubic root of 1991291411 is about 1258.0897001392.

The spelling of 1991291411 in words is "one billion, nine hundred ninety-one million, two hundred ninety-one thousand, four hundred eleven".