1991127011317 has 2 divisors, whose sum is σ = 1991127011318. Its totient is φ = 1991127011316.

The previous prime is 1991127011311. The next prime is 1991127011351. The reversal of 1991127011317 is 7131107211991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1588472039716 + 402654971601 = 1260346^2 + 634551^2 .

It is a cyclic number.

It is not a de Polignac number, because 1991127011317 - 2³⁹ = 1441371197429 is a prime.

It is a super-4 number, since 4×1991127011317⁴ (a number of 50 digits) contains 4444 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1991127011311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 995563505658 + 995563505659.

It is an arithmetic number, because the mean of its divisors is an integer number (995563505659).

Almost surely, 2^{1991127011317} is an apocalyptic number.

It is an amenable number.

1991127011317 is a deficient number, since it is larger than the sum of its proper divisors (1).

1991127011317 is an equidigital number, since it uses as much as digits as its factorization.

1991127011317 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23814, while the sum is 43.

The spelling of 1991127011317 in words is "one trillion, nine hundred ninety-one billion, one hundred twenty-seven million, eleven thousand, three hundred seventeen".