11981989173901 has 2 divisors, whose sum is σ = 11981989173902. Its totient is φ = 11981989173900.

The previous prime is 11981989173899. The next prime is 11981989173941. The reversal of 11981989173901 is 10937198918911.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11981989173001 + 900 = 3461501^2 + 30^2 .

It is an emirp because it is prime and its reverse (10937198918911) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 11981989173901 - 2¹ = 11981989173899 is a prime.

Together with 11981989173899, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11981989173941) 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, 5990994586950 + 5990994586951.

It is an arithmetic number, because the mean of its divisors is an integer number (5990994586951).

Almost surely, 2^{11981989173901} is an apocalyptic number.

It is an amenable number.

11981989173901 is a deficient number, since it is larger than the sum of its proper divisors (1).

11981989173901 is an equidigital number, since it uses as much as digits as its factorization.

11981989173901 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8817984, while the sum is 67.

The spelling of 11981989173901 in words is "eleven trillion, nine hundred eighty-one billion, nine hundred eighty-nine million, one hundred seventy-three thousand, nine hundred one".