2005530661 has 4 divisors (see below), whose sum is σ = 2005624800. Its totient is φ = 2005436524.

The previous prime is 2005530643. The next prime is 2005530671. The reversal of 2005530661 is 1660355002.

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 a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1660355002 = 2 ⋅830177501.

It is a cyclic number.

It is not a de Polignac number, because 2005530661 - 2⁵ = 2005530629 is a prime.

It is a super-2 number, since 2×2005530661² = 8044306464422193842, which 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 (2005530671) 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, 1800 + ... + 63358.

It is an arithmetic number, because the mean of its divisors is an integer number (501406200).

Almost surely, 2^2005530661 is an apocalyptic number.

It is an amenable number.

2005530661 is a deficient number, since it is larger than the sum of its proper divisors (94139).

2005530661 is an equidigital number, since it uses as much as digits as its factorization.

2005530661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94138.

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 2005530661 is about 44783.1515304584. The cubic root of 2005530661 is about 1261.0813470518.

Adding to 2005530661 its reverse (1660355002), we get a palindrome (3665885663).

The spelling of 2005530661 in words is "two billion, five million, five hundred thirty thousand, six hundred sixty-one".