121721191 has 2 divisors, whose sum is σ = 121721192. Its totient is φ = 121721190.

The previous prime is 121721179. The next prime is 121721203. The reversal of 121721191 is 191127121.

It is a balanced prime because it is at equal distance from previous prime (121721179) and next prime (121721203).

It is a cyclic number.

It is not a de Polignac number, because 121721191 - 2⁹ = 121720679 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121721101) 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, 60860595 + 60860596.

It is an arithmetic number, because the mean of its divisors is an integer number (60860596).

Almost surely, 2^121721191 is an apocalyptic number.

121721191 is a deficient number, since it is larger than the sum of its proper divisors (1).

121721191 is an equidigital number, since it uses as much as digits as its factorization.

121721191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 252, while the sum is 25.

The square root of 121721191 is about 11032.7327077202. The cubic root of 121721191 is about 495.5894633970.

The spelling of 121721191 in words is "one hundred twenty-one million, seven hundred twenty-one thousand, one hundred ninety-one".