121211100991 has 2 divisors, whose sum is σ = 121211100992. Its totient is φ = 121211100990.

The previous prime is 121211100961. The next prime is 121211101009. The reversal of 121211100991 is 199001112121.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121211100991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121211100961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60605550495 + 60605550496.

It is an arithmetic number, because the mean of its divisors is an integer number (60605550496).

Almost surely, 2^121211100991 is an apocalyptic number.

121211100991 is a deficient number, since it is larger than the sum of its proper divisors (1).

121211100991 is an equidigital number, since it uses as much as digits as its factorization.

121211100991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324, while the sum is 28.

It can be divided in two parts, 121 and 211100991, that added together give a palindrome (211101112).

The spelling of 121211100991 in words is "one hundred twenty-one billion, two hundred eleven million, one hundred thousand, nine hundred ninety-one".