831561 has 8 divisors (see below), whose sum is σ = 1119360. Its totient is φ = 549072.

The previous prime is 831559. The next prime is 831583. The reversal of 831561 is 165138.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 831561 - 2¹ = 831559 is a prime.

It is not an unprimeable number, because it can be changed into a prime (831541) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 945 + ... + 1598.

It is an arithmetic number, because the mean of its divisors is an integer number (139920).

2⁸³¹⁵⁶¹ is an apocalyptic number.

It is an amenable number.

831561 is a deficient number, since it is larger than the sum of its proper divisors (287799).

831561 is a wasteful number, since it uses less digits than its factorization.

831561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2655.

The product of its digits is 720, while the sum is 24.

The square root of 831561 is about 911.8996655334. The cubic root of 831561 is about 94.0368423561.

Adding to 831561 its reverse (165138), we get a palindrome (996699).

The spelling of 831561 in words is "eight hundred thirty-one thousand, five hundred sixty-one".