231221957 has 2 divisors, whose sum is σ = 231221958. Its totient is φ = 231221956.

The previous prime is 231221951. The next prime is 231221983. The reversal of 231221957 is 759122132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 155775361 + 75446596 = 12481^2 + 8686^2 .

It is a cyclic number.

It is not a de Polignac number, because 231221957 - 2⁴ = 231221941 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 (231221951) 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, 115610978 + 115610979.

It is an arithmetic number, because the mean of its divisors is an integer number (115610979).

Almost surely, 2^231221957 is an apocalyptic number.

It is an amenable number.

231221957 is a deficient number, since it is larger than the sum of its proper divisors (1).

231221957 is an equidigital number, since it uses as much as digits as its factorization.

231221957 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7560, while the sum is 32.

The square root of 231221957 is about 15205.9842496301. The cubic root of 231221957 is about 613.7757008386.

The spelling of 231221957 in words is "two hundred thirty-one million, two hundred twenty-one thousand, nine hundred fifty-seven".