810005338661 has 4 divisors (see below), whose sum is σ = 815164608492. Its totient is φ = 804846068832.

The previous prime is 810005338657. The next prime is 810005338669. The reversal of 810005338661 is 166833500018.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 233476441636 + 576528897025 = 483194^2 + 759295^2 .

It is a cyclic number.

It is not a de Polignac number, because 810005338661 - 2² = 810005338657 is a prime.

It is a super-2 number, since 2×810005338661² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (810005338669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2579634680 + ... + 2579634993.

It is an arithmetic number, because the mean of its divisors is an integer number (203791152123).

Almost surely, 2^810005338661 is an apocalyptic number.

It is an amenable number.

810005338661 is a deficient number, since it is larger than the sum of its proper divisors (5159269831).

810005338661 is a wasteful number, since it uses less digits than its factorization.

810005338661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5159269830.

The product of its (nonzero) digits is 103680, while the sum is 41.

Adding to 810005338661 its reverse (166833500018), we get a palindrome (976838838679).

The spelling of 810005338661 in words is "eight hundred ten billion, five million, three hundred thirty-eight thousand, six hundred sixty-one".