831661 has 2 divisors, whose sum is σ = 831662. Its totient is φ = 831660.

The previous prime is 831659. The next prime is 831679. The reversal of 831661 is 166138.

831661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 656100 + 175561 = 810^2 + 419^2 .

It is a cyclic number.

It is not a de Polignac number, because 831661 - 2¹ = 831659 is a prime.

Together with 831659, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (831631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 415830 + 415831.

It is an arithmetic number, because the mean of its divisors is an integer number (415831).

2⁸³¹⁶⁶¹ is an apocalyptic number.

It is an amenable number.

831661 is a deficient number, since it is larger than the sum of its proper divisors (1).

831661 is an equidigital number, since it uses as much as digits as its factorization.

831661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 25.

The square root of 831661 is about 911.9544944788. The cubic root of 831661 is about 94.0406116956.

Adding to 831661 its reverse (166138), we get a palindrome (997799).

The spelling of 831661 in words is "eight hundred thirty-one thousand, six hundred sixty-one".