12128381 has 2 divisors, whose sum is σ = 12128382. Its totient is φ = 12128380.

The previous prime is 12128357. The next prime is 12128387. The reversal of 12128381 is 18382121.

12128381 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11256025 + 872356 = 3355^2 + 934^2 .

It is an emirp because it is prime and its reverse (18382121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12128381 - 2¹⁴ = 12111997 is a prime.

It is a super-2 number, since 2×12128381² = 294195251362322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 12128381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12128387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6064190 + 6064191.

It is an arithmetic number, because the mean of its divisors is an integer number (6064191).

Almost surely, 2^12128381 is an apocalyptic number.

It is an amenable number.

12128381 is a deficient number, since it is larger than the sum of its proper divisors (1).

12128381 is an equidigital number, since it uses as much as digits as its factorization.

12128381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 768, while the sum is 26.

The square root of 12128381 is about 3482.5825187639. The cubic root of 12128381 is about 229.7563961430.

The spelling of 12128381 in words is "twelve million, one hundred twenty-eight thousand, three hundred eighty-one".