1278427385 has 4 divisors (see below), whose sum is σ = 1534112868. Its totient is φ = 1022741904.

The previous prime is 1278427379. The next prime is 1278427393. The reversal of 1278427385 is 5837248721.

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

It can be written as a sum of positive squares in 2 ways, for example, as 810483961 + 467943424 = 28469^2 + 21632^2 .

It is a cyclic number.

It is not a de Polignac number, because 1278427385 - 2¹⁰ = 1278426361 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 127842734 + ... + 127842743.

It is an arithmetic number, because the mean of its divisors is an integer number (383528217).

Almost surely, 2^1278427385 is an apocalyptic number.

It is an amenable number.

1278427385 is a deficient number, since it is larger than the sum of its proper divisors (255685483).

1278427385 is an equidigital number, since it uses as much as digits as its factorization.

1278427385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 255685482.

The product of its digits is 752640, while the sum is 47.

The square root of 1278427385 is about 35755.1029225200. The cubic root of 1278427385 is about 1085.3222046327.

The spelling of 1278427385 in words is "one billion, two hundred seventy-eight million, four hundred twenty-seven thousand, three hundred eighty-five".