861439 has 2 divisors, whose sum is σ = 861440. Its totient is φ = 861438.

The previous prime is 861437. The next prime is 861491. The reversal of 861439 is 934168.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 861439 - 2¹ = 861437 is a prime.

Together with 861437, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 861439.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (861433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430719 + 430720.

It is an arithmetic number, because the mean of its divisors is an integer number (430720).

2⁸⁶¹⁴³⁹ is an apocalyptic number.

861439 is a deficient number, since it is larger than the sum of its proper divisors (1).

861439 is an equidigital number, since it uses as much as digits as its factorization.

861439 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 31.

The square root of 861439 is about 928.1373820723. The cubic root of 861439 is about 95.1498650293.

The spelling of 861439 in words is "eight hundred sixty-one thousand, four hundred thirty-nine".