12381557 has 2 divisors, whose sum is σ = 12381558. Its totient is φ = 12381556.

The previous prime is 12381517. The next prime is 12381583. The reversal of 12381557 is 75518321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12117361 + 264196 = 3481^2 + 514^2 .

It is an emirp because it is prime and its reverse (75518321) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12381557 - 2¹⁴ = 12365173 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12381517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6190778 + 6190779.

It is an arithmetic number, because the mean of its divisors is an integer number (6190779).

Almost surely, 2^12381557 is an apocalyptic number.

It is an amenable number.

12381557 is a deficient number, since it is larger than the sum of its proper divisors (1).

12381557 is an equidigital number, since it uses as much as digits as its factorization.

12381557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8400, while the sum is 32.

The square root of 12381557 is about 3518.7436678451. The cubic root of 12381557 is about 231.3440959169.

Adding to 12381557 its reverse (75518321), we get a palindrome (87899878).

The spelling of 12381557 in words is "twelve million, three hundred eighty-one thousand, five hundred fifty-seven".