18135852821641 has 9 divisors (see below), whose sum is σ = 18782919592021. Its totient is φ = 17510359345024.

The previous prime is 18135852821617. The next prime is 18135852821663. The reversal of 18135852821641 is 14612825853181.

The square root of 18135852821641 is 4258621.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 4028767538041 + 14107085283600 = 2007179^2 + 3755940^2 .

It is not a de Polignac number, because 18135852821641 - 2⁵ = 18135852821609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18135852821941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 123426585 + ... + 123573433.

Almost surely, 2^{18135852821641} is an apocalyptic number.

18135852821641 is the 4258621-st square number.

18135852821641 is the 2129311-st centered octagonal number.

It is an amenable number.

18135852821641 is a deficient number, since it is larger than the sum of its proper divisors (647066770380).

18135852821641 is an frugal number, since it uses more digits than its factorization.

18135852821641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 293756 (or 146878 counting only the distinct ones).

The product of its digits is 3686400, while the sum is 55.

The spelling of 18135852821641 in words is "eighteen trillion, one hundred thirty-five billion, eight hundred fifty-two million, eight hundred twenty-one thousand, six hundred forty-one".