1278256385 has 56 divisors (see below), whose sum is σ = 1867793256. Its totient is φ = 839005440.

The previous prime is 1278256327. The next prime is 1278256393. The reversal of 1278256385 is 5836528721.

It can be written as a sum of positive squares in 4 ways, for example, as 30118144 + 1248138241 = 5488^2 + 35329^2 .

It is not a de Polignac number, because 1278256385 - 2¹² = 1278252289 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 24118019 + ... + 24118071.

It is an arithmetic number, because the mean of its divisors is an integer number (33353451).

Almost surely, 2^1278256385 is an apocalyptic number.

It is an amenable number.

1278256385 is a deficient number, since it is larger than the sum of its proper divisors (589536871).

1278256385 is an frugal number, since it uses more digits than its factorization.

1278256385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141 (or 106 counting only the distinct ones).

The product of its digits is 806400, while the sum is 47.

The square root of 1278256385 is about 35752.7115754875. The cubic root of 1278256385 is about 1085.2738122681.

The spelling of 1278256385 in words is "one billion, two hundred seventy-eight million, two hundred fifty-six thousand, three hundred eighty-five".