816231440 has 20 divisors (see below), whose sum is σ = 1897738284. Its totient is φ = 326492544.

The previous prime is 816231439. The next prime is 816231443. The reversal of 816231440 is 44132618.

It can be written as a sum of positive squares in 2 ways, for example, as 490356736 + 325874704 = 22144^2 + 18052^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (816231443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5101367 + ... + 5101526.

Almost surely, 2^816231440 is an apocalyptic number.

816231440 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

816231440 is an abundant number, since it is smaller than the sum of its proper divisors (1081506844).

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

816231440 is a wasteful number, since it uses less digits than its factorization.

816231440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10202906 (or 10202900 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 816231440 is about 28569.7644372508. The cubic root of 816231440 is about 934.5540840323.

The spelling of 816231440 in words is "eight hundred sixteen million, two hundred thirty-one thousand, four hundred forty".