12780121 has 2 divisors, whose sum is σ = 12780122. Its totient is φ = 12780120.

The previous prime is 12780113. The next prime is 12780127. The reversal of 12780121 is 12108721.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11128896 + 1651225 = 3336^2 + 1285^2 .

It is a cyclic number.

It is not a de Polignac number, because 12780121 - 2³ = 12780113 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 12780092 and 12780101.

It is not a weakly prime, because it can be changed into another prime (12780127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6390060 + 6390061.

It is an arithmetic number, because the mean of its divisors is an integer number (6390061).

Almost surely, 2^12780121 is an apocalyptic number.

It is an amenable number.

12780121 is a deficient number, since it is larger than the sum of its proper divisors (1).

12780121 is an equidigital number, since it uses as much as digits as its factorization.

12780121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 224, while the sum is 22.

The square root of 12780121 is about 3574.9295097946. The cubic root of 12780121 is about 233.8002593368.

Adding to 12780121 its reverse (12108721), we get a palindrome (24888842).

The spelling of 12780121 in words is "twelve million, seven hundred eighty thousand, one hundred twenty-one".