816564872 has 12 divisors (see below), whose sum is σ = 1531210695. Its totient is φ = 408242024.

The previous prime is 816564871. The next prime is 816564907. The reversal of 816564872 is 278465618.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in only one way, i.e., 408282436 + 408282436 = 20206^2 + 20206^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=20206.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (816564871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 75773 + ... + 85875.

Almost surely, 2^816564872 is an apocalyptic number.

It is an amenable number.

816564872 is a deficient number, since it is larger than the sum of its proper divisors (714645823).

816564872 is an frugal number, since it uses more digits than its factorization.

816564872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20212 (or 10105 counting only the distinct ones).

The product of its digits is 645120, while the sum is 47.

The square root of 816564872 is about 28575.5992413108. The cubic root of 816564872 is about 934.6813223786.

It can be divided in two parts, 8165 and 64872, that added together give a palindrome (73037).

The spelling of 816564872 in words is "eight hundred sixteen million, five hundred sixty-four thousand, eight hundred seventy-two".