818671661 has 2 divisors, whose sum is σ = 818671662. Its totient is φ = 818671660.

The previous prime is 818671631. The next prime is 818671691. The reversal of 818671661 is 166176818.

818671661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a balanced prime because it is at equal distance from previous prime (818671631) and next prime (818671691).

It can be written as a sum of positive squares in only one way, i.e., 812820100 + 5851561 = 28510^2 + 2419^2 .

It is a cyclic number.

It is not a de Polignac number, because 818671661 - 2⁶ = 818671597 is a prime.

It is a super-3 number, since 3×818671661³ (a number of 28 digits) contains 333 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (818671621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 409335830 + 409335831.

It is an arithmetic number, because the mean of its divisors is an integer number (409335831).

Almost surely, 2^818671661 is an apocalyptic number.

It is an amenable number.

818671661 is a deficient number, since it is larger than the sum of its proper divisors (1).

818671661 is an equidigital number, since it uses as much as digits as its factorization.

818671661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96768, while the sum is 44.

The square root of 818671661 is about 28612.4389208610. The cubic root of 818671661 is about 935.4844776804.

The spelling of 818671661 in words is "eight hundred eighteen million, six hundred seventy-one thousand, six hundred sixty-one".