1171997975861 has 2 divisors, whose sum is σ = 1171997975862. Its totient is φ = 1171997975860.

The previous prime is 1171997975821. The next prime is 1171997975899. The reversal of 1171997975861 is 1685797991711.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1081204836100 + 90793139761 = 1039810^2 + 301319^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1171997975861 is a prime.

It is a super-2 number, since 2×1171997975861² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1171997975821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 585998987930 + 585998987931.

It is an arithmetic number, because the mean of its divisors is an integer number (585998987931).

Almost surely, 2^{1171997975861} is an apocalyptic number.

It is an amenable number.

1171997975861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1171997975861 is an equidigital number, since it uses as much as digits as its factorization.

1171997975861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60011280, while the sum is 71.

The spelling of 1171997975861 in words is "one trillion, one hundred seventy-one billion, nine hundred ninety-seven million, nine hundred seventy-five thousand, eight hundred sixty-one".