1278448709 has 2 divisors, whose sum is σ = 1278448710. Its totient is φ = 1278448708.

The previous prime is 1278448663. The next prime is 1278448727. The reversal of 1278448709 is 9078448721.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1073872900 + 204575809 = 32770^2 + 14303^2 .

It is an emirp because it is prime and its reverse (9078448721) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1278448709 - 2⁸ = 1278448453 is a prime.

It is a super-2 number, since 2×1278448709² = 3268862203087533362, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1278448729) 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, 639224354 + 639224355.

It is an arithmetic number, because the mean of its divisors is an integer number (639224355).

Almost surely, 2^1278448709 is an apocalyptic number.

It is an amenable number.

1278448709 is a deficient number, since it is larger than the sum of its proper divisors (1).

1278448709 is an equidigital number, since it uses as much as digits as its factorization.

1278448709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 903168, while the sum is 50.

The square root of 1278448709 is about 35755.4011164747. The cubic root of 1278448709 is about 1085.3282389428.

The spelling of 1278448709 in words is "one billion, two hundred seventy-eight million, four hundred forty-eight thousand, seven hundred nine".