1805098561 has 4 divisors (see below), whose sum is σ = 2062969792. Its totient is φ = 1547227332.

The previous prime is 1805098549. The next prime is 1805098577. The reversal of 1805098561 is 1658905081.

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: 1658905081 = 929 ⋅1785689.

It is not a de Polignac number, because 1805098561 - 2¹⁵ = 1805065793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1805098501) 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, 128935605 + ... + 128935618.

It is an arithmetic number, because the mean of its divisors is an integer number (515742448).

Almost surely, 2^1805098561 is an apocalyptic number.

It is an amenable number.

1805098561 is a deficient number, since it is larger than the sum of its proper divisors (257871231).

1805098561 is an equidigital number, since it uses as much as digits as its factorization.

1805098561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257871230.

The product of its (nonzero) digits is 86400, while the sum is 43.

The square root of 1805098561 is about 42486.4514992721. The cubic root of 1805098561 is about 1217.5878526135.

It can be divided in two parts, 18050 and 98561, that added together give a palindrome (116611).

The spelling of 1805098561 in words is "one billion, eight hundred five million, ninety-eight thousand, five hundred sixty-one".