821533420 has 12 divisors (see below), whose sum is σ = 1725220224. Its totient is φ = 328613360.

The previous prime is 821533417. The next prime is 821533439. The reversal of 821533420 is 24335128.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20538316 + ... + 20538355.

It is an arithmetic number, because the mean of its divisors is an integer number (143768352).

Almost surely, 2^821533420 is an apocalyptic number.

It is an amenable number.

821533420 is an abundant number, since it is smaller than the sum of its proper divisors (903686804).

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

821533420 is a wasteful number, since it uses less digits than its factorization.

821533420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41076680 (or 41076678 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 821533420 is about 28662.4042955227. The cubic root of 821533420 is about 936.5732404857.

Adding to 821533420 its reverse (24335128), we get a palindrome (845868548).

The spelling of 821533420 in words is "eight hundred twenty-one million, five hundred thirty-three thousand, four hundred twenty".