231211091 has 2 divisors, whose sum is σ = 231211092. Its totient is φ = 231211090.

The previous prime is 231211087. The next prime is 231211103. The reversal of 231211091 is 190112132.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 231211091 - 2² = 231211087 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (231211031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115605545 + 115605546.

It is an arithmetic number, because the mean of its divisors is an integer number (115605546).

Almost surely, 2^231211091 is an apocalyptic number.

231211091 is a deficient number, since it is larger than the sum of its proper divisors (1).

231211091 is an equidigital number, since it uses as much as digits as its factorization.

231211091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108, while the sum is 20.

The square root of 231211091 is about 15205.6269518886. The cubic root of 231211091 is about 613.7660861357.

The spelling of 231211091 in words is "two hundred thirty-one million, two hundred eleven thousand, ninety-one".