861139 has 2 divisors, whose sum is σ = 861140. Its totient is φ = 861138.

The previous prime is 861131. The next prime is 861163. The reversal of 861139 is 931168.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 861139 - 2³ = 861131 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (861131) 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, 430569 + 430570.

It is an arithmetic number, because the mean of its divisors is an integer number (430570).

2⁸⁶¹¹³⁹ is an apocalyptic number.

861139 is a deficient number, since it is larger than the sum of its proper divisors (1).

861139 is an equidigital number, since it uses as much as digits as its factorization.

861139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1296, while the sum is 28.

The square root of 861139 is about 927.9757539936. The cubic root of 861139 is about 95.1388182909.

It can be divided in two parts, 861 and 139, that added together give a cube (1000 = 10³).

The spelling of 861139 in words is "eight hundred sixty-one thousand, one hundred thirty-nine".