816168641 has 4 divisors (see below), whose sum is σ = 816548484. Its totient is φ = 815788800.

The previous prime is 816168611. The next prime is 816168659. The reversal of 816168641 is 146861618.

816168641 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 146861618 = 2 ⋅73430809.

It can be written as a sum of positive squares in 2 ways, for example, as 388878400 + 427290241 = 19720^2 + 20671^2 .

It is a cyclic number.

It is not a de Polignac number, because 816168641 - 2²² = 811974337 is a prime.

It is a super-2 number, since 2×816168641² = 1332262501103573762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (816168611) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 186680 + ... + 191001.

It is an arithmetic number, because the mean of its divisors is an integer number (204137121).

Almost surely, 2^816168641 is an apocalyptic number.

It is an amenable number.

816168641 is a deficient number, since it is larger than the sum of its proper divisors (379843).

816168641 is a wasteful number, since it uses less digits than its factorization.

816168641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 379842.

The product of its digits is 55296, while the sum is 41.

The square root of 816168641 is about 28568.6653695968. The cubic root of 816168641 is about 934.5301159255.

The spelling of 816168641 in words is "eight hundred sixteen million, one hundred sixty-eight thousand, six hundred forty-one".