231091261 has 2 divisors, whose sum is σ = 231091262. Its totient is φ = 231091260.

The previous prime is 231091247. The next prime is 231091271. The reversal of 231091261 is 162190132.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 230128900 + 962361 = 15170^2 + 981^2 .

It is a cyclic number.

It is not a de Polignac number, because 231091261 - 2¹¹ = 231089213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231091271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115545630 + 115545631.

It is an arithmetic number, because the mean of its divisors is an integer number (115545631).

Almost surely, 2^231091261 is an apocalyptic number.

It is an amenable number.

231091261 is a deficient number, since it is larger than the sum of its proper divisors (1).

231091261 is an equidigital number, since it uses as much as digits as its factorization.

231091261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 231091261 is about 15201.6861235851. The cubic root of 231091261 is about 613.6600354278.

The spelling of 231091261 in words is "two hundred thirty-one million, ninety-one thousand, two hundred sixty-one".