12205661 has 12 divisors (see below), whose sum is σ = 13596156. Its totient is φ = 10892160.

The previous prime is 12205649. The next prime is 12205691. The reversal of 12205661 is 16650221.

12205661 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 6943225 + 5262436 = 2635^2 + 2294^2 .

It is not a de Polignac number, because 12205661 - 2¹⁸ = 11943517 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12205601) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12005 + ... + 12981.

It is an arithmetic number, because the mean of its divisors is an integer number (1133013).

Almost surely, 2^12205661 is an apocalyptic number.

It is an amenable number.

12205661 is a deficient number, since it is larger than the sum of its proper divisors (1390495).

12205661 is an equidigital number, since it uses as much as digits as its factorization.

12205661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1052 (or 1021 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 12205661 is about 3493.6601151228. The cubic root of 12205661 is about 230.2433530139.

Adding to 12205661 its reverse (16650221), we get a palindrome (28855882).

The spelling of 12205661 in words is "twelve million, two hundred five thousand, six hundred sixty-one".