861568 has 32 divisors (see below), whose sum is σ = 1762560. Its totient is φ = 419328.

The previous prime is 861563. The next prime is 861571. The reversal of 861568 is 865168.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861563) by changing a digit.

861568 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 (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6721 + ... + 6847.

It is an arithmetic number, because the mean of its divisors is an integer number (55080).

2⁸⁶¹⁵⁶⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 861568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (881280).

861568 is an abundant number, since it is smaller than the sum of its proper divisors (900992).

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

861568 is a wasteful number, since it uses less digits than its factorization.

861568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194 (or 182 counting only the distinct ones).

The product of its digits is 11520, while the sum is 34.

The square root of 861568 is about 928.2068734932. The cubic root of 861568 is about 95.1546143383.

Subtracting 861568 from its reverse (865168), we obtain a square (3600 = 60²).

The spelling of 861568 in words is "eight hundred sixty-one thousand, five hundred sixty-eight".