1268645921 has 2 divisors, whose sum is σ = 1268645922. Its totient is φ = 1268645920.

The previous prime is 1268645909. The next prime is 1268645947. The reversal of 1268645921 is 1295468621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1100580625 + 168065296 = 33175^2 + 12964^2 .

It is a cyclic number.

It is not a de Polignac number, because 1268645921 - 2⁶ = 1268645857 is a prime.

It is not a weakly prime, because it can be changed into another prime (1268645321) 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 as a sum of consecutive naturals, namely, 634322960 + 634322961.

It is an arithmetic number, because the mean of its divisors is an integer number (634322961).

Almost surely, 2^1268645921 is an apocalyptic number.

It is an amenable number.

1268645921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1268645921 is an equidigital number, since it uses as much as digits as its factorization.

1268645921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 207360, while the sum is 44.

The square root of 1268645921 is about 35618.0561092264. The cubic root of 1268645921 is about 1082.5471204645.

The spelling of 1268645921 in words is "one billion, two hundred sixty-eight million, six hundred forty-five thousand, nine hundred twenty-one".