820221824 has 32 divisors (see below), whose sum is σ = 1641292200. Its totient is φ = 408289792.

The previous prime is 820221823. The next prime is 820221917. The reversal of 820221824 is 428122028.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820221823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14942 + ... + 43170.

Almost surely, 2^820221824 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 820221824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (820646100).

820221824 is an abundant number, since it is smaller than the sum of its proper divisors (821070376).

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

820221824 is a wasteful number, since it uses less digits than its factorization.

820221824 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28470 (or 28458 counting only the distinct ones).

The product of its (nonzero) digits is 4096, while the sum is 29.

The square root of 820221824 is about 28639.5150796937. The cubic root of 820221824 is about 936.0745551444.

The spelling of 820221824 in words is "eight hundred twenty million, two hundred twenty-one thousand, eight hundred twenty-four".