11998121 has 2 divisors, whose sum is σ = 11998122. Its totient is φ = 11998120.

The previous prime is 11998067. The next prime is 11998123. The reversal of 11998121 is 12189911.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11978521 + 19600 = 3461^2 + 140^2 .

It is an emirp because it is prime and its reverse (12189911) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11998121 is a prime.

Together with 11998123, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (11998123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5999060 + 5999061.

It is an arithmetic number, because the mean of its divisors is an integer number (5999061).

Almost surely, 2^11998121 is an apocalyptic number.

It is an amenable number.

11998121 is a deficient number, since it is larger than the sum of its proper divisors (1).

11998121 is an equidigital number, since it uses as much as digits as its factorization.

11998121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1296, while the sum is 32.

The square root of 11998121 is about 3463.8303942312. The cubic root of 11998121 is about 228.9308983421.

The spelling of 11998121 in words is "eleven million, nine hundred ninety-eight thousand, one hundred twenty-one".