831221 has 2 divisors, whose sum is σ = 831222. Its totient is φ = 831220.

The previous prime is 831217. The next prime is 831239. The reversal of 831221 is 122138.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 784996 + 46225 = 886^2 + 215^2 .

It is a cyclic number.

It is not a de Polignac number, because 831221 - 2² = 831217 is a prime.

It is a Chen prime.

It is a plaindrome in base 14.

It is a self number, because there is not a number n which added to its sum of digits gives 831221.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 831221.

It is not a weakly prime, because it can be changed into another prime (831821) 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, 415610 + 415611.

It is an arithmetic number, because the mean of its divisors is an integer number (415611).

2⁸³¹²²¹ is an apocalyptic number.

It is an amenable number.

831221 is a deficient number, since it is larger than the sum of its proper divisors (1).

831221 is an equidigital number, since it uses as much as digits as its factorization.

831221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96, while the sum is 17.

The square root of 831221 is about 911.7132224554. The cubic root of 831221 is about 94.0240243407.

Adding to 831221 its reverse (122138), we get a palindrome (953359).

The spelling of 831221 in words is "eight hundred thirty-one thousand, two hundred twenty-one".