12778189 has 2 divisors, whose sum is σ = 12778190. Its totient is φ = 12778188.

The previous prime is 12778187. The next prime is 12778201. The reversal of 12778189 is 98187721.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9715689 + 3062500 = 3117^2 + 1750^2 .

It is an emirp because it is prime and its reverse (98187721) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12778189 - 2¹ = 12778187 is a prime.

It is a super-2 number, since 2×12778189² = 326564228239442, which contains 22 as substring.

Together with 12778187, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12778187) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6389094 + 6389095.

It is an arithmetic number, because the mean of its divisors is an integer number (6389095).

Almost surely, 2^12778189 is an apocalyptic number.

It is an amenable number.

12778189 is a deficient number, since it is larger than the sum of its proper divisors (1).

12778189 is an equidigital number, since it uses as much as digits as its factorization.

12778189 is an evil number, because the sum of its binary digits is even.

The product of its digits is 56448, while the sum is 43.

The square root of 12778189 is about 3574.6592844633. The cubic root of 12778189 is about 233.7884773705.

The spelling of 12778189 in words is "twelve million, seven hundred seventy-eight thousand, one hundred eighty-nine".