816521472 has 270 divisors, whose sum is σ = 2647727082. Its totient is φ = 250159104.

The previous prime is 816521467. The next prime is 816521483. The reversal of 816521472 is 274125618.

816521472 is a `hidden beast` number, since 8 + 165 + 21 + 472 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 19927296 + 796594176 = 4464^2 + 28224^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an alternating number because its digits alternate between even and odd.

It is an unprimeable number.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 3504268 + ... + 3504500.

Almost surely, 2^816521472 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 816521472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1323863541).

816521472 is an abundant number, since it is smaller than the sum of its proper divisors (1831205610).

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

816521472 is a wasteful number, since it uses less digits than its factorization.

816521472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287 (or 251 counting only the distinct ones).

The product of its digits is 26880, while the sum is 36.

The square root of 816521472 is about 28574.8398420709. The cubic root of 816521472 is about 934.6647628092.

The spelling of 816521472 in words is "eight hundred sixteen million, five hundred twenty-one thousand, four hundred seventy-two".