128831 has 2 divisors, whose sum is σ = 128832. Its totient is φ = 128830.

The previous prime is 128819. The next prime is 128833. The reversal of 128831 is 138821.

128831 is nontrivially palindromic in base 14.

It is a strong prime.

It is an emirp because it is prime and its reverse (138821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 128831 - 2⁶ = 128767 is a prime.

It is a super-2 number, since 2×128831² = 33194853122, which contains 22 as substring.

Together with 128833, 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 = 128797 and 128806.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128833) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64415 + 64416.

It is an arithmetic number, because the mean of its divisors is an integer number (64416).

2¹²⁸⁸³¹ is an apocalyptic number.

128831 is a deficient number, since it is larger than the sum of its proper divisors (1).

128831 is an equidigital number, since it uses as much as digits as its factorization.

128831 is an evil number, because the sum of its binary digits is even.

The product of its digits is 384, while the sum is 23.

The square root of 128831 is about 358.9303553616. The cubic root of 128831 is about 50.5056687425.

It can be divided in two parts, 128 and 831, that added together give a palindrome (959).

The spelling of 128831 in words is "one hundred twenty-eight thousand, eight hundred thirty-one".