821860 has 48 divisors (see below), whose sum is σ = 1940400. Its totient is φ = 290304.

The previous prime is 821857. The next prime is 821861. The reversal of 821860 is 68128.

821860 = T₄₁ + T₄₂ + ... + T₁₇₀.

It can be written as a sum of positive squares in 8 ways, for example, as 19044 + 802816 = 138^2 + 896^2 .

It is a plaindrome in base 15.

It is a zygodrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (821861) 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, 7486 + ... + 7594.

It is an arithmetic number, because the mean of its divisors is an integer number (40425).

2⁸²¹⁸⁶⁰ 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 821860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (970200).

821860 is an abundant number, since it is smaller than the sum of its proper divisors (1118540).

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

821860 is a wasteful number, since it uses less digits than its factorization.

821860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160 (or 158 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 821860 is about 906.5649452742. The cubic root of 821860 is about 93.6697327776.

Adding to 821860 its reverse (68128), we get a palindrome (889988).

It can be divided in two parts, 821 and 860, that added together give a square (1681 = 41²).

The spelling of 821860 in words is "eight hundred twenty-one thousand, eight hundred sixty".