1256045909 has 2 divisors, whose sum is σ = 1256045910. Its totient is φ = 1256045908.

The previous prime is 1256045899. The next prime is 1256045927. The reversal of 1256045909 is 9095406521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1128288100 + 127757809 = 33590^2 + 11303^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1256045909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1256045509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 628022954 + 628022955.

It is an arithmetic number, because the mean of its divisors is an integer number (628022955).

Almost surely, 2^1256045909 is an apocalyptic number.

It is an amenable number.

1256045909 is a deficient number, since it is larger than the sum of its proper divisors (1).

1256045909 is an equidigital number, since it uses as much as digits as its factorization.

1256045909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 97200, while the sum is 41.

The square root of 1256045909 is about 35440.7379861086. The cubic root of 1256045909 is about 1078.9512879547.

The spelling of 1256045909 in words is "one billion, two hundred fifty-six million, forty-five thousand, nine hundred nine".