11205645661 has 4 divisors (see below), whose sum is σ = 12806452192. Its totient is φ = 9604839132.

The previous prime is 11205645653. The next prime is 11205645667. The reversal of 11205645661 is 16654650211.

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: 16654650211 = 31 ⋅537246781.

It is not a de Polignac number, because 11205645661 - 2³ = 11205645653 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 11205645661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11205645667) 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 3 ways as a sum of consecutive naturals, for example, 800403255 + ... + 800403268.

It is an arithmetic number, because the mean of its divisors is an integer number (3201613048).

Almost surely, 2^11205645661 is an apocalyptic number.

It is an amenable number.

11205645661 is a deficient number, since it is larger than the sum of its proper divisors (1600806531).

11205645661 is an equidigital number, since it uses as much as digits as its factorization.

11205645661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1600806530.

The product of its (nonzero) digits is 43200, while the sum is 37.

The spelling of 11205645661 in words is "eleven billion, two hundred five million, six hundred forty-five thousand, six hundred sixty-one".