1278331939 has 2 divisors, whose sum is σ = 1278331940. Its totient is φ = 1278331938.

The previous prime is 1278331877. The next prime is 1278331969. The reversal of 1278331939 is 9391338721.

It is a strong prime.

It is an emirp because it is prime and its reverse (9391338721) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1278331939 - 2⁷ = 1278331811 is a prime.

It is not a weakly prime, because it can be changed into another prime (1278331969) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639165969 + 639165970.

It is an arithmetic number, because the mean of its divisors is an integer number (639165970).

Almost surely, 2^1278331939 is an apocalyptic number.

1278331939 is a deficient number, since it is larger than the sum of its proper divisors (1).

1278331939 is an equidigital number, since it uses as much as digits as its factorization.

1278331939 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 244944, while the sum is 46.

The square root of 1278331939 is about 35753.7681790325. The cubic root of 1278331939 is about 1085.2951943015.

The spelling of 1278331939 in words is "one billion, two hundred seventy-eight million, three hundred thirty-one thousand, nine hundred thirty-nine".