1278247221 has 12 divisors (see below), whose sum is σ = 1954966572. Its totient is φ = 802037376.

The previous prime is 1278247219. The next prime is 1278247237. The reversal of 1278247221 is 1227428721.

It can be written as a sum of positive squares in 2 ways, for example, as 652547025 + 625700196 = 25545^2 + 25014^2 .

It is not a de Polignac number, because 1278247221 - 2¹ = 1278247219 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1278247721) 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, 4177126 + ... + 4177431.

It is an arithmetic number, because the mean of its divisors is an integer number (162913881).

Almost surely, 2^1278247221 is an apocalyptic number.

It is an amenable number.

1278247221 is a deficient number, since it is larger than the sum of its proper divisors (676719351).

1278247221 is a wasteful number, since it uses less digits than its factorization.

1278247221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8354580 (or 8354577 counting only the distinct ones).

The product of its digits is 25088, while the sum is 36.

The square root of 1278247221 is about 35752.5834171462. The cubic root of 1278247221 is about 1085.2712187683.

The spelling of 1278247221 in words is "one billion, two hundred seventy-eight million, two hundred forty-seven thousand, two hundred twenty-one".