1278216549 has 6 divisors (see below), whose sum is σ = 1846312806. Its totient is φ = 852144360.

The previous prime is 1278216539. The next prime is 1278216607. The reversal of 1278216549 is 9456128721.

1278216549 is a `hidden beast` number, since 1 + 27 + 82 + 1 + 6 + 549 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1196675649 + 81540900 = 34593^2 + 9030^2 .

It is not a de Polignac number, because 1278216549 - 2⁸ = 1278216293 is a prime.

It is a super-2 number, since 2×1278216549² = 3267675092274938802, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1278216539) 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 5 ways as a sum of consecutive naturals, for example, 71012022 + ... + 71012039.

It is an arithmetic number, because the mean of its divisors is an integer number (307718801).

Almost surely, 2^1278216549 is an apocalyptic number.

It is an amenable number.

1278216549 is a deficient number, since it is larger than the sum of its proper divisors (568096257).

1278216549 is a wasteful number, since it uses less digits than its factorization.

1278216549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142024067 (or 142024064 counting only the distinct ones).

The product of its digits is 241920, while the sum is 45.

The square root of 1278216549 is about 35752.1544665493. The cubic root of 1278216549 is about 1085.2625382083.

The spelling of 1278216549 in words is "one billion, two hundred seventy-eight million, two hundred sixteen thousand, five hundred forty-nine".