121115101981 has 2 divisors, whose sum is σ = 121115101982. Its totient is φ = 121115101980.

The previous prime is 121115101979. The next prime is 121115101999. The reversal of 121115101981 is 189101511121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 112650181956 + 8464920025 = 335634^2 + 92005^2 .

It is an emirp because it is prime and its reverse (189101511121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 121115101981 - 2¹ = 121115101979 is a prime.

It is a super-2 number, since 2×121115101981² (a number of 23 digits) contains 22 as substring.

Together with 121115101979, 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 (121115101381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60557550990 + 60557550991.

It is an arithmetic number, because the mean of its divisors is an integer number (60557550991).

Almost surely, 2^121115101981 is an apocalyptic number.

It is an amenable number.

121115101981 is a deficient number, since it is larger than the sum of its proper divisors (1).

121115101981 is an equidigital number, since it uses as much as digits as its factorization.

121115101981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 720, while the sum is 31.

The spelling of 121115101981 in words is "one hundred twenty-one billion, one hundred fifteen million, one hundred one thousand, nine hundred eighty-one".