1278251065 has 16 divisors (see below), whose sum is σ = 1887879168. Its totient is φ = 809090496.

The previous prime is 1278251041. The next prime is 1278251069. The reversal of 1278251065 is 5601528721.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1278251065 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1278251069) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1404217 + ... + 1405126.

It is an arithmetic number, because the mean of its divisors is an integer number (117992448).

Almost surely, 2^1278251065 is an apocalyptic number.

It is an amenable number.

1278251065 is a deficient number, since it is larger than the sum of its proper divisors (609628103).

1278251065 is a wasteful number, since it uses less digits than its factorization.

1278251065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2809368.

The product of its (nonzero) digits is 33600, while the sum is 37.

The square root of 1278251065 is about 35752.6371754588. The cubic root of 1278251065 is about 1085.2723066586.

Adding to 1278251065 its reverse (5601528721), we get a palindrome (6879779786).

The spelling of 1278251065 in words is "one billion, two hundred seventy-eight million, two hundred fifty-one thousand, sixty-five".