821797228 has 54 divisors (see below), whose sum is σ = 1729047348. Its totient is φ = 340759440.

The previous prime is 821797219. The next prime is 821797237. The reversal of 821797228 is 822797128.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (821797219) and next prime (821797237).

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 186175 + ... + 190537.

Almost surely, 2^821797228 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 821797228, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (864523674).

821797228 is an abundant number, since it is smaller than the sum of its proper divisors (907250120).

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

821797228 is a wasteful number, since it uses less digits than its factorization.

821797228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4443 (or 4403 counting only the distinct ones).

The product of its digits is 225792, while the sum is 46.

The square root of 821797228 is about 28667.0059127213. The cubic root of 821797228 is about 936.6734794882.

The spelling of 821797228 in words is "eight hundred twenty-one million, seven hundred ninety-seven thousand, two hundred twenty-eight".