1171997975881 has 4 divisors (see below), whose sum is σ = 1172561167764. Its totient is φ = 1171434784000.

The previous prime is 1171997975861. The next prime is 1171997975899. The reversal of 1171997975881 is 1885797991711.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 850895553600 + 321102422281 = 922440^2 + 566659^2 .

It is a cyclic number.

It is not a de Polignac number, because 1171997975881 - 2¹⁹ = 1171997451593 is a prime.

It is a super-2 number, since 2×1171997975881² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1171997975821) 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, 281592820 + ... + 281596981.

It is an arithmetic number, because the mean of its divisors is an integer number (293140291941).

Almost surely, 2^{1171997975881} is an apocalyptic number.

It is an amenable number.

1171997975881 is a deficient number, since it is larger than the sum of its proper divisors (563191883).

1171997975881 is an equidigital number, since it uses as much as digits as its factorization.

1171997975881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 563191882.

The product of its digits is 80015040, while the sum is 73.

The spelling of 1171997975881 in words is "one trillion, one hundred seventy-one billion, nine hundred ninety-seven million, nine hundred seventy-five thousand, eight hundred eighty-one".