231221189 has 2 divisors, whose sum is σ = 231221190. Its totient is φ = 231221188.

The previous prime is 231221183. The next prime is 231221201. The reversal of 231221189 is 981122132.

231221189 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 131560900 + 99660289 = 11470^2 + 9983^2 .

It is a cyclic number.

It is not a de Polignac number, because 231221189 - 2⁴ = 231221173 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231221183) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115610594 + 115610595.

It is an arithmetic number, because the mean of its divisors is an integer number (115610595).

Almost surely, 2^231221189 is an apocalyptic number.

It is an amenable number.

231221189 is a deficient number, since it is larger than the sum of its proper divisors (1).

231221189 is an equidigital number, since it uses as much as digits as its factorization.

231221189 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 29.

The square root of 231221189 is about 15205.9589963935. The cubic root of 231221189 is about 613.7750212892.

The spelling of 231221189 in words is "two hundred thirty-one million, two hundred twenty-one thousand, one hundred eighty-nine".