861540 has 48 divisors (see below), whose sum is σ = 2455488. Its totient is φ = 225664.

The previous prime is 861499. The next prime is 861541. The reversal of 861540 is 45168.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 861540.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861541) by changing a digit.

861540 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4894 + ... + 5066.

It is an arithmetic number, because the mean of its divisors is an integer number (51156).

2⁸⁶¹⁵⁴⁰ 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 861540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1227744).

861540 is an abundant number, since it is smaller than the sum of its proper divisors (1593948).

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

861540 is a wasteful number, since it uses less digits than its factorization.

861540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268 (or 266 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 861540 is about 928.1917905261. The cubic root of 861540 is about 95.1535835208.

The spelling of 861540 in words is "eight hundred sixty-one thousand, five hundred forty".