1268945257 has 4 divisors (see below), whose sum is σ = 1312702020. Its totient is φ = 1225188496.

The previous prime is 1268945233. The next prime is 1268945287. The reversal of 1268945257 is 7525498621.

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 1072497001 + 196448256 = 32749^2 + 14016^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1268945257 is a prime.

It is a super-2 number, since 2×1268945257² = 3220444130525592098, which contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1268945257.

It is not an unprimeable number, because it can be changed into a prime (1268945287) 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, 21878338 + ... + 21878395.

It is an arithmetic number, because the mean of its divisors is an integer number (328175505).

Almost surely, 2^1268945257 is an apocalyptic number.

It is an amenable number.

1268945257 is a deficient number, since it is larger than the sum of its proper divisors (43756763).

1268945257 is an equidigital number, since it uses as much as digits as its factorization.

1268945257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43756762.

The product of its digits is 1209600, while the sum is 49.

The square root of 1268945257 is about 35622.2578874501. The cubic root of 1268945257 is about 1082.6322558141.

The spelling of 1268945257 in words is "one billion, two hundred sixty-eight million, nine hundred forty-five thousand, two hundred fifty-seven".