42731231 has 2 divisors, whose sum is σ = 42731232. Its totient is φ = 42731230.

The previous prime is 42731219. The next prime is 42731233. The reversal of 42731231 is 13213724.

42731231 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42731231 is a prime.

It is a super-2 number, since 2×42731231² = 3651916205550722, which contains 22 as substring.

Together with 42731233, 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 = 42731197 and 42731206.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42731233) 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, 21365615 + 21365616.

It is an arithmetic number, because the mean of its divisors is an integer number (21365616).

Almost surely, 2^42731231 is an apocalyptic number.

42731231 is a deficient number, since it is larger than the sum of its proper divisors (1).

42731231 is an equidigital number, since it uses as much as digits as its factorization.

42731231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1008, while the sum is 23.

The square root of 42731231 is about 6536.9129564344. The cubic root of 42731231 is about 349.6083537522.

Adding to 42731231 its reverse (13213724), we get a palindrome (55944955).

The spelling of 42731231 in words is "forty-two million, seven hundred thirty-one thousand, two hundred thirty-one".