1288125778 has 4 divisors (see below), whose sum is σ = 1932188670. Its totient is φ = 644062888.

The previous prime is 1288125763. The next prime is 1288125803. The reversal of 1288125778 is 8775218821.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 1247714329 + 40411449 = 35323^2 + 6357^2 .

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322031443 + ... + 322031446.

Almost surely, 2^1288125778 is an apocalyptic number.

1288125778 is a deficient number, since it is larger than the sum of its proper divisors (644062892).

1288125778 is an equidigital number, since it uses as much as digits as its factorization.

1288125778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 644062891.

The product of its digits is 501760, while the sum is 49.

The square root of 1288125778 is about 35890.4691805499. The cubic root of 1288125778 is about 1088.0597804748.

The spelling of 1288125778 in words is "one billion, two hundred eighty-eight million, one hundred twenty-five thousand, seven hundred seventy-eight".