861228 has 36 divisors (see below), whose sum is σ = 2227680. Its totient is φ = 280416.

The previous prime is 861221. The next prime is 861239. The reversal of 861228 is 822168.

It is a tau number, because it is divible by the number of its divisors (36).

It is not an unprimeable number, because it can be changed into a prime (861221) by changing a digit.

861228 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 11 ways as a sum of consecutive naturals, for example, 1438 + ... + 1946.

It is an arithmetic number, because the mean of its divisors is an integer number (61880).

2⁸⁶¹²²⁸ 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 861228, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1113840).

861228 is an abundant number, since it is smaller than the sum of its proper divisors (1366452).

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

861228 is a wasteful number, since it uses less digits than its factorization.

861228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 566 (or 561 counting only the distinct ones).

The product of its digits is 1536, while the sum is 27.

The square root of 861228 is about 928.0237065937. The cubic root of 861228 is about 95.1420957576.

Subtracting from 861228 its reverse (822168), we obtain a triangular number (39060 = T₂₇₉).

It can be divided in two parts, 861 and 228, that added together give a square (1089 = 33²).

The spelling of 861228 in words is "eight hundred sixty-one thousand, two hundred twenty-eight".