1278799913 has 4 divisors (see below), whose sum is σ = 1299763908. Its totient is φ = 1257835920.

The previous prime is 1278799909. The next prime is 1278799927. The reversal of 1278799913 is 3199978721.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 280998169 + 997801744 = 16763^2 + 31588^2 .

It is a cyclic number.

It is not a de Polignac number, because 1278799913 - 2² = 1278799909 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1278799943) 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 in 3 ways as a sum of consecutive naturals, for example, 10481906 + ... + 10482027.

It is an arithmetic number, because the mean of its divisors is an integer number (324940977).

Almost surely, 2^1278799913 is an apocalyptic number.

It is an amenable number.

1278799913 is a deficient number, since it is larger than the sum of its proper divisors (20963995).

1278799913 is an equidigital number, since it uses as much as digits as its factorization.

1278799913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20963994.

The product of its digits is 1714608, while the sum is 56.

The square root of 1278799913 is about 35760.3119813013. The cubic root of 1278799913 is about 1085.4276137339.

The spelling of 1278799913 in words is "one billion, two hundred seventy-eight million, seven hundred ninety-nine thousand, nine hundred thirteen".