205540094581 has 4 divisors (see below), whose sum is σ = 206514218464. Its totient is φ = 204565970700.

The previous prime is 205540094579. The next prime is 205540094609. The reversal of 205540094581 is 185490045502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 185490045502 = 2 ⋅92745022751.

It is a cyclic number.

It is not a de Polignac number, because 205540094581 - 2¹ = 205540094579 is a prime.

It is a super-2 number, since 2×205540094581² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205540044581) 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 3 ways as a sum of consecutive naturals, for example, 487061625 + ... + 487062046.

It is an arithmetic number, because the mean of its divisors is an integer number (51628554616).

Almost surely, 2^205540094581 is an apocalyptic number.

It is an amenable number.

205540094581 is a deficient number, since it is larger than the sum of its proper divisors (974123883).

205540094581 is an equidigital number, since it uses as much as digits as its factorization.

205540094581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 974123882.

The product of its (nonzero) digits is 288000, while the sum is 43.

The spelling of 205540094581 in words is "two hundred five billion, five hundred forty million, ninety-four thousand, five hundred eighty-one".