11989191551881 has 2 divisors, whose sum is σ = 11989191551882. Its totient is φ = 11989191551880.

The previous prime is 11989191551849. The next prime is 11989191551917. The reversal of 11989191551881 is 18815519198911.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11527491686656 + 461699865225 = 3395216^2 + 679485^2 .

It is a cyclic number.

It is not a de Polignac number, because 11989191551881 - 2⁵ = 11989191551849 is a prime.

It is a super-2 number, since 2×11989191551881² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (11989191554881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5994595775940 + 5994595775941.

It is an arithmetic number, because the mean of its divisors is an integer number (5994595775941).

Almost surely, 2^{11989191551881} is an apocalyptic number.

It is an amenable number.

11989191551881 is a deficient number, since it is larger than the sum of its proper divisors (1).

11989191551881 is an equidigital number, since it uses as much as digits as its factorization.

11989191551881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9331200, while the sum is 67.

The spelling of 11989191551881 in words is "eleven trillion, nine hundred eighty-nine billion, one hundred ninety-one million, five hundred fifty-one thousand, eight hundred eighty-one".