1272646778 has 16 divisors (see below), whose sum is σ = 2078916840. Its totient is φ = 580774656.

The previous prime is 1272646747. The next prime is 1272646889. The reversal of 1272646778 is 8776462721.

It can be written as a sum of positive squares in 4 ways, for example, as 996854329 + 275792449 = 31573^2 + 16607^2 .

It is a Curzon number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 272675 + ... + 277302.

Almost surely, 2^1272646778 is an apocalyptic number.

1272646778 is a deficient number, since it is larger than the sum of its proper divisors (806270062).

1272646778 is a wasteful number, since it uses less digits than its factorization.

1272646778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 550081.

The product of its digits is 1580544, while the sum is 50.

The square root of 1272646778 is about 35674.1752252242. The cubic root of 1272646778 is about 1083.6839155258.

The spelling of 1272646778 in words is "one billion, two hundred seventy-two million, six hundred forty-six thousand, seven hundred seventy-eight".