121159991 has 2 divisors, whose sum is σ = 121159992. Its totient is φ = 121159990.

The previous prime is 121159967. The next prime is 121159993. The reversal of 121159991 is 199951121.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 121159991 - 2¹⁰ = 121158967 is a prime.

Together with 121159993, 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 (121159993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60579995 + 60579996.

It is an arithmetic number, because the mean of its divisors is an integer number (60579996).

Almost surely, 2^121159991 is an apocalyptic number.

121159991 is a deficient number, since it is larger than the sum of its proper divisors (1).

121159991 is an equidigital number, since it uses as much as digits as its factorization.

121159991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7290, while the sum is 38.

The square root of 121159991 is about 11007.2699158329. The cubic root of 121159991 is about 494.8266454148.

The spelling of 121159991 in words is "one hundred twenty-one million, one hundred fifty-nine thousand, nine hundred ninety-one".