31128191 has 2 divisors, whose sum is σ = 31128192. Its totient is φ = 31128190.

The previous prime is 31128179. The next prime is 31128193. The reversal of 31128191 is 19182113.

It is a strong prime.

It is an emirp because it is prime and its reverse (19182113) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31128191 - 2⁶ = 31128127 is a prime.

Together with 31128193, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31128191.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31128193) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15564095 + 15564096.

It is an arithmetic number, because the mean of its divisors is an integer number (15564096).

Almost surely, 2^31128191 is an apocalyptic number.

31128191 is a deficient number, since it is larger than the sum of its proper divisors (1).

31128191 is an equidigital number, since it uses as much as digits as its factorization.

31128191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 432, while the sum is 26.

The square root of 31128191 is about 5579.2643780341. The cubic root of 31128191 is about 314.5704769839.

The spelling of 31128191 in words is "thirty-one million, one hundred twenty-eight thousand, one hundred ninety-one".