1278917625 has 16 divisors (see below), whose sum is σ = 2128119552. Its totient is φ = 682089200.

The previous prime is 1278917609. The next prime is 1278917639. The reversal of 1278917625 is 5267198721.

It is not a de Polignac number, because 1278917625 - 2⁴ = 1278917609 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1704849 + ... + 1705598.

It is an arithmetic number, because the mean of its divisors is an integer number (133007472).

Almost surely, 2^1278917625 is an apocalyptic number.

1278917625 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1278917625 is a deficient number, since it is larger than the sum of its proper divisors (849201927).

1278917625 is an equidigital number, since it uses as much as digits as its factorization.

1278917625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3410465 (or 3410455 counting only the distinct ones).

The product of its digits is 423360, while the sum is 48.

The square root of 1278917625 is about 35761.9577903671. The cubic root of 1278917625 is about 1085.4609168159.

The spelling of 1278917625 in words is "one billion, two hundred seventy-eight million, nine hundred seventeen thousand, six hundred twenty-five".