861031 has 2 divisors, whose sum is σ = 861032. Its totient is φ = 861030.

The previous prime is 861019. The next prime is 861037. The reversal of 861031 is 130168.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-861031 is a prime.

It is a super-2 number, since 2×861031² = 1482748765922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (861037) 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, 430515 + 430516.

It is an arithmetic number, because the mean of its divisors is an integer number (430516).

2⁸⁶¹⁰³¹ is an apocalyptic number.

861031 is a deficient number, since it is larger than the sum of its proper divisors (1).

861031 is an equidigital number, since it uses as much as digits as its factorization.

861031 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 861031 is about 927.9175609934. The cubic root of 861031 is about 95.1348408371.

Adding to 861031 its reverse (130168), we get a palindrome (991199).

The spelling of 861031 in words is "eight hundred sixty-one thousand, thirty-one".