821140 has 12 divisors (see below), whose sum is σ = 1724436. Its totient is φ = 328448.

The previous prime is 821131. The next prime is 821143. The reversal of 821140 is 41128.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 174724 + 646416 = 418^2 + 804^2 .

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821143) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20509 + ... + 20548.

It is an arithmetic number, because the mean of its divisors is an integer number (143703).

2⁸²¹¹⁴⁰ is an apocalyptic number.

It is an amenable number.

821140 is an abundant number, since it is smaller than the sum of its proper divisors (903296).

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

821140 is a wasteful number, since it uses less digits than its factorization.

821140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41066 (or 41064 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

The square root of 821140 is about 906.1677548887. The cubic root of 821140 is about 93.6423713001.

Adding to 821140 its reverse (41128), we get a palindrome (862268).

It can be divided in two parts, 821 and 140, that added together give a square (961 = 31²).

The spelling of 821140 in words is "eight hundred twenty-one thousand, one hundred forty".