121212111989 has 2 divisors, whose sum is σ = 121212111990. Its totient is φ = 121212111988.

The previous prime is 121212111973. The next prime is 121212111991. The reversal of 121212111989 is 989111212121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 61025303089 + 60186808900 = 247033^2 + 245330^2 .

It is a cyclic number.

It is not a de Polignac number, because 121212111989 - 2⁴ = 121212111973 is a prime.

It is a super-2 number, since 2×121212111989² (a number of 23 digits) contains 22 as substring.

Together with 121212111991, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121212111959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60606055994 + 60606055995.

It is an arithmetic number, because the mean of its divisors is an integer number (60606055995).

Almost surely, 2^121212111989 is an apocalyptic number.

It is an amenable number.

121212111989 is a deficient number, since it is larger than the sum of its proper divisors (1).

121212111989 is an equidigital number, since it uses as much as digits as its factorization.

121212111989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 38.

The spelling of 121212111989 in words is "one hundred twenty-one billion, two hundred twelve million, one hundred eleven thousand, nine hundred eighty-nine".