12209861 has 2 divisors, whose sum is σ = 12209862. Its totient is φ = 12209860.

The previous prime is 12209833. The next prime is 12209867. The reversal of 12209861 is 16890221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6300100 + 5909761 = 2510^2 + 2431^2 .

It is a cyclic number.

It is not a de Polignac number, because 12209861 - 2¹⁸ = 11947717 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12209867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6104930 + 6104931.

It is an arithmetic number, because the mean of its divisors is an integer number (6104931).

Almost surely, 2^12209861 is an apocalyptic number.

It is an amenable number.

12209861 is a deficient number, since it is larger than the sum of its proper divisors (1).

12209861 is an equidigital number, since it uses as much as digits as its factorization.

12209861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 12209861 is about 3494.2611522323. The cubic root of 12209861 is about 230.2697590995.

The spelling of 12209861 in words is "twelve million, two hundred nine thousand, eight hundred sixty-one".