1281376189 has 2 divisors, whose sum is σ = 1281376190. Its totient is φ = 1281376188.

The previous prime is 1281376079. The next prime is 1281376237. The reversal of 1281376189 is 9816731821.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1249056964 + 32319225 = 35342^2 + 5685^2 .

It is a cyclic number.

It is not a de Polignac number, because 1281376189 - 2⁹ = 1281375677 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1281346189) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 640688094 + 640688095.

It is an arithmetic number, because the mean of its divisors is an integer number (640688095).

Almost surely, 2^1281376189 is an apocalyptic number.

It is an amenable number.

1281376189 is a deficient number, since it is larger than the sum of its proper divisors (1).

1281376189 is an equidigital number, since it uses as much as digits as its factorization.

1281376189 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 46.

The square root of 1281376189 is about 35796.3152992036. The cubic root of 1281376189 is about 1086.1560272325.

The spelling of 1281376189 in words is "one billion, two hundred eighty-one million, three hundred seventy-six thousand, one hundred eighty-nine".