1278216499 has 12 divisors (see below), whose sum is σ = 1538179200. Its totient is φ = 1057833168.

The previous prime is 1278216491. The next prime is 1278216539. The reversal of 1278216499 is 9946128721.

It is not a de Polignac number, because 1278216499 - 2³ = 1278216491 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1278216491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 448339 + ... + 451180.

It is an arithmetic number, because the mean of its divisors is an integer number (128181600).

Almost surely, 2^1278216499 is an apocalyptic number.

1278216499 is a deficient number, since it is larger than the sum of its proper divisors (259962701).

1278216499 is an equidigital number, since it uses as much as digits as its factorization.

1278216499 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 899562 (or 899555 counting only the distinct ones).

The product of its digits is 435456, while the sum is 49.

The square root of 1278216499 is about 35752.1537672907. The cubic root of 1278216499 is about 1085.2625240576.

The spelling of 1278216499 in words is "one billion, two hundred seventy-eight million, two hundred sixteen thousand, four hundred ninety-nine".