861558 has 8 divisors (see below), whose sum is σ = 1723128. Its totient is φ = 287184.

The previous prime is 861551. The next prime is 861559. The reversal of 861558 is 855168.

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

861558 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861551) by changing a digit.

861558 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 in 3 ways as a sum of consecutive naturals, for example, 71791 + ... + 71802.

It is an arithmetic number, because the mean of its divisors is an integer number (215391).

2⁸⁶¹⁵⁵⁸ is an apocalyptic number.

861558 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

861558 is a wasteful number, since it uses less digits than its factorization.

861558 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143598.

The product of its digits is 9600, while the sum is 33.

The square root of 861558 is about 928.2014867474. The cubic root of 861558 is about 95.1542461918.

The spelling of 861558 in words is "eight hundred sixty-one thousand, five hundred fifty-eight".