1278331979 has 2 divisors, whose sum is σ = 1278331980. Its totient is φ = 1278331978.

The previous prime is 1278331969. The next prime is 1278331997. The reversal of 1278331979 is 9791338721.

Together with next prime (1278331997) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1278331979 - 2¹⁶ = 1278266443 is a prime.

It is not a weakly prime, because it can be changed into another prime (1278331939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639165989 + 639165990.

It is an arithmetic number, because the mean of its divisors is an integer number (639165990).

Almost surely, 2^1278331979 is an apocalyptic number.

1278331979 is a deficient number, since it is larger than the sum of its proper divisors (1).

1278331979 is an equidigital number, since it uses as much as digits as its factorization.

1278331979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 571536, while the sum is 50.

The square root of 1278331979 is about 35753.7687384141. The cubic root of 1278331979 is about 1085.2952056214.

The spelling of 1278331979 in words is "one billion, two hundred seventy-eight million, three hundred thirty-one thousand, nine hundred seventy-nine".