205541636689 has 3 divisors (see below), whose sum is σ = 205542090057. Its totient is φ = 205541183322.

The previous prime is 205541636683. The next prime is 205541636737. The reversal of 205541636689 is 986636145502.

The square root of 205541636689 is 453367.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 205541636689 - 2¹³ = 205541628497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (205541636683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 226684 + ... + 680050.

It is an arithmetic number, because the mean of its divisors is an integer number (68514030019).

Almost surely, 2^205541636689 is an apocalyptic number.

205541636689 is the 453367-th square number.

205541636689 is the 226684-th centered octagonal number.

It is an amenable number.

205541636689 is a deficient number, since it is larger than the sum of its proper divisors (453368).

205541636689 is an frugal number, since it uses more digits than its factorization.

205541636689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 906734 (or 453367 counting only the distinct ones).

The product of its (nonzero) digits is 9331200, while the sum is 55.

The spelling of 205541636689 in words is "two hundred five billion, five hundred forty-one million, six hundred thirty-six thousand, six hundred eighty-nine".