1278257317 has 4 divisors (see below), whose sum is σ = 1319491456. Its totient is φ = 1237023180.

The previous prime is 1278257297. The next prime is 1278257327. The reversal of 1278257317 is 7137528721.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 7137528721 = 1399 ⋅5101879.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1278257317 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1278257327) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20617023 + ... + 20617084.

It is an arithmetic number, because the mean of its divisors is an integer number (329872864).

Almost surely, 2^1278257317 is an apocalyptic number.

It is an amenable number.

1278257317 is a deficient number, since it is larger than the sum of its proper divisors (41234139).

1278257317 is an equidigital number, since it uses as much as digits as its factorization.

1278257317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41234138.

The product of its digits is 164640, while the sum is 43.

The square root of 1278257317 is about 35752.7246094616. The cubic root of 1278257317 is about 1085.2740760323.

The spelling of 1278257317 in words is "one billion, two hundred seventy-eight million, two hundred fifty-seven thousand, three hundred seventeen".