861131 has 2 divisors, whose sum is σ = 861132. Its totient is φ = 861130.

The previous prime is 861121. The next prime is 861139. The reversal of 861131 is 131168.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 861131 - 2¹⁰ = 860107 is a prime.

It is a super-3 number, since 3×861131³ = 1915706293446333273, which contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (861139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430565 + 430566.

It is an arithmetic number, because the mean of its divisors is an integer number (430566).

2⁸⁶¹¹³¹ is an apocalyptic number.

861131 is a deficient number, since it is larger than the sum of its proper divisors (1).

861131 is an equidigital number, since it uses as much as digits as its factorization.

861131 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 144, while the sum is 20.

The square root of 861131 is about 927.9714435261. The cubic root of 861131 is about 95.1385236761.

Adding to 861131 its reverse (131168), we get a palindrome (992299).

The spelling of 861131 in words is "eight hundred sixty-one thousand, one hundred thirty-one".