231331421 has 2 divisors, whose sum is σ = 231331422. Its totient is φ = 231331420.

The previous prime is 231331409. The next prime is 231331423. The reversal of 231331421 is 124133132.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 211848025 + 19483396 = 14555^2 + 4414^2 .

It is a cyclic number.

It is not a de Polignac number, because 231331421 - 2¹⁸ = 231069277 is a prime.

Together with 231331423, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 231331393 and 231331402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231331423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115665710 + 115665711.

It is an arithmetic number, because the mean of its divisors is an integer number (115665711).

Almost surely, 2^231331421 is an apocalyptic number.

It is an amenable number.

231331421 is a deficient number, since it is larger than the sum of its proper divisors (1).

231331421 is an equidigital number, since it uses as much as digits as its factorization.

231331421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 432, while the sum is 20.

The square root of 231331421 is about 15209.5831961300. The cubic root of 231331421 is about 613.8725424832.

Adding to 231331421 its reverse (124133132), we get a palindrome (355464553).

The spelling of 231331421 in words is "two hundred thirty-one million, three hundred thirty-one thousand, four hundred twenty-one".