1278240531649 has 9 divisors (see below), whose sum is σ = 1280670261097. Its totient is φ = 1275815409664.

The previous prime is 1278240531643. The next prime is 1278240531713. The reversal of 1278240531649 is 9461350428721.

The square root of 1278240531649 is 1130593.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 675182673025 + 603057858624 = 821695^2 + 776568^2 .

It is not a de Polignac number, because 1278240531649 - 2²⁵ = 1278206977217 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1278240531596 and 1278240531605.

It is not an unprimeable number, because it can be changed into a prime (1278240531643) 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 8 ways as a sum of consecutive naturals, for example, 1050320289 + ... + 1050321505.

It is a 1-persistent number, because it is pandigital, but 2⋅1278240531649 = 2556481063298 is not.

Almost surely, 2^{1278240531649} is an apocalyptic number.

1278240531649 is the 1130593-rd square number.

1278240531649 is the 565297-th centered octagonal number.

It is an amenable number.

1278240531649 is a deficient number, since it is larger than the sum of its proper divisors (2429729448).

1278240531649 is an frugal number, since it uses more digits than its factorization.

1278240531649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4292 (or 2146 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 52.

The spelling of 1278240531649 in words is "one trillion, two hundred seventy-eight billion, two hundred forty million, five hundred thirty-one thousand, six hundred forty-nine".