861138 has 32 divisors (see below), whose sum is σ = 1969920. Its totient is φ = 278640.

The previous prime is 861131. The next prime is 861139. The reversal of 861138 is 831168.

861138 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (861131) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1783 + ... + 2213.

It is an arithmetic number, because the mean of its divisors is an integer number (61560).

2⁸⁶¹¹³⁸ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 861138, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (984960).

861138 is an abundant number, since it is smaller than the sum of its proper divisors (1108782).

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

861138 is a wasteful number, since it uses less digits than its factorization.

861138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 479 (or 473 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 861138 is about 927.9752151863. The cubic root of 861138 is about 95.1387814642.

It can be divided in two parts, 8611 and 38, that added together give a square (8649 = 93²).

The spelling of 861138 in words is "eight hundred sixty-one thousand, one hundred thirty-eight".