1279216399 has 4 divisors (see below), whose sum is σ = 1279458136. Its totient is φ = 1278974664.

The previous prime is 1279216397. The next prime is 1279216403. The reversal of 1279216399 is 9936129721.

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

It is a cyclic number.

It is not a de Polignac number, because 1279216399 - 2¹ = 1279216397 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1279216397) 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 in 3 ways as a sum of consecutive naturals, for example, 112749 + ... + 123574.

It is an arithmetic number, because the mean of its divisors is an integer number (319864534).

Almost surely, 2^1279216399 is an apocalyptic number.

1279216399 is a deficient number, since it is larger than the sum of its proper divisors (241737).

1279216399 is an equidigital number, since it uses as much as digits as its factorization.

1279216399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241736.

The product of its digits is 367416, while the sum is 49.

The square root of 1279216399 is about 35766.1348065457. The cubic root of 1279216399 is about 1085.5454367888.

The spelling of 1279216399 in words is "one billion, two hundred seventy-nine million, two hundred sixteen thousand, three hundred ninety-nine".