821988 has 60 divisors (see below), whose sum is σ = 2236080. Its totient is φ = 263088.

The previous prime is 821971. The next prime is 821993. The reversal of 821988 is 889128.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 13903 + ... + 13961.

It is an arithmetic number, because the mean of its divisors is an integer number (37268).

2⁸²¹⁹⁸⁸ 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 821988, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1118040).

821988 is an abundant number, since it is smaller than the sum of its proper divisors (1414092).

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

821988 is a wasteful number, since it uses less digits than its factorization.

821988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118 (or 107 counting only the distinct ones).

The product of its digits is 9216, while the sum is 36.

The square root of 821988 is about 906.6355386813. The cubic root of 821988 is about 93.6745953671.

The spelling of 821988 in words is "eight hundred twenty-one thousand, nine hundred eighty-eight".