1268721218 has 4 divisors (see below), whose sum is σ = 1903081830. Its totient is φ = 634360608.

The previous prime is 1268721197. The next prime is 1268721241. The reversal of 1268721218 is 8121278621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8121278621 = 2237 ⋅3630433.

It can be written as a sum of positive squares in only one way, i.e., 677404729 + 591316489 = 26027^2 + 24317^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 317180303 + ... + 317180306.

Almost surely, 2^1268721218 is an apocalyptic number.

1268721218 is a deficient number, since it is larger than the sum of its proper divisors (634360612).

1268721218 is an equidigital number, since it uses as much as digits as its factorization.

1268721218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 634360611.

The product of its digits is 21504, while the sum is 38.

The square root of 1268721218 is about 35619.1130995706. The cubic root of 1268721218 is about 1082.5685372461.

Adding to 1268721218 its reverse (8121278621), we get a palindrome (9389999839).

The spelling of 1268721218 in words is "one billion, two hundred sixty-eight million, seven hundred twenty-one thousand, two hundred eighteen".