12121661 has 2 divisors, whose sum is σ = 12121662. Its totient is φ = 12121660.

The previous prime is 12121631. The next prime is 12121673. The reversal of 12121661 is 16612121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9211225 + 2910436 = 3035^2 + 1706^2 .

It is an emirp because it is prime and its reverse (16612121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12121661 - 2²² = 7927357 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 (12121631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6060830 + 6060831.

It is an arithmetic number, because the mean of its divisors is an integer number (6060831).

Almost surely, 2^12121661 is an apocalyptic number.

It is an amenable number.

12121661 is a deficient number, since it is larger than the sum of its proper divisors (1).

12121661 is an equidigital number, since it uses as much as digits as its factorization.

12121661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 144, while the sum is 20.

The square root of 12121661 is about 3481.6175838251. The cubic root of 12121661 is about 229.7139544182.

Adding to 12121661 its reverse (16612121), we get a palindrome (28733782).

The spelling of 12121661 in words is "twelve million, one hundred twenty-one thousand, six hundred sixty-one".