821964 has 48 divisors (see below), whose sum is σ = 2257920. Its totient is φ = 229440.

The previous prime is 821941. The next prime is 821971. The reversal of 821964 is 469128.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1477 + ... + 1955.

It is an arithmetic number, because the mean of its divisors is an integer number (47040).

2⁸²¹⁹⁶⁴ 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 821964, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1128960).

821964 is an abundant number, since it is smaller than the sum of its proper divisors (1435956).

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

821964 is a wasteful number, since it uses less digits than its factorization.

821964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 510 (or 508 counting only the distinct ones).

The product of its digits is 3456, while the sum is 30.

The square root of 821964 is about 906.6223028362. The cubic root of 821964 is about 93.6736836700.

Subtracting from 821964 its reverse (469128), we obtain a square (352836 = 594²).

The spelling of 821964 in words is "eight hundred twenty-one thousand, nine hundred sixty-four".