816821946 has 48 divisors (see below), whose sum is σ = 1849053960. Its totient is φ = 260265600.

The previous prime is 816821939. The next prime is 816821959. The reversal of 816821946 is 649128618.

It can be written as a sum of positive squares in 4 ways, for example, as 708890625 + 107931321 = 26625^2 + 10389^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 44976 + ... + 60468.

Almost surely, 2^816821946 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 816821946, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (924526980).

816821946 is an abundant number, since it is smaller than the sum of its proper divisors (1032232014).

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

816821946 is a wasteful number, since it uses less digits than its factorization.

816821946 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15631 (or 15628 counting only the distinct ones).

The product of its digits is 165888, while the sum is 45.

The square root of 816821946 is about 28580.0970257275. The cubic root of 816821946 is about 934.7793987077.

The spelling of 816821946 in words is "eight hundred sixteen million, eight hundred twenty-one thousand, nine hundred forty-six".