1991296771 has 2 divisors, whose sum is σ = 1991296772. Its totient is φ = 1991296770.

The previous prime is 1991296763. The next prime is 1991296823. The reversal of 1991296771 is 1776921991.

It is an a-pointer prime, because the next prime (1991296823) can be obtained adding 1991296771 to its sum of digits (52).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1991296771 - 2³ = 1991296763 is a prime.

It is not a weakly prime, because it can be changed into another prime (1991296711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 995648385 + 995648386.

It is an arithmetic number, because the mean of its divisors is an integer number (995648386).

Almost surely, 2^1991296771 is an apocalyptic number.

1991296771 is a deficient number, since it is larger than the sum of its proper divisors (1).

1991296771 is an equidigital number, since it uses as much as digits as its factorization.

1991296771 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 428652, while the sum is 52.

The square root of 1991296771 is about 44623.9484021753. The cubic root of 1991296771 is about 1258.0908289468.

The spelling of 1991296771 in words is "one billion, nine hundred ninety-one million, two hundred ninety-six thousand, seven hundred seventy-one".