1256809363109 has 4 divisors (see below), whose sum is σ = 1283549987904. Its totient is φ = 1230068738316.

The previous prime is 1256809363099. The next prime is 1256809363111. The reversal of 1256809363109 is 9013639086521.

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.

It is a cyclic number.

It is not a de Polignac number, because 1256809363109 - 2⁴ = 1256809363093 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 (1256809363169) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13370312327 + ... + 13370312420.

It is an arithmetic number, because the mean of its divisors is an integer number (320887496976).

Almost surely, 2^{1256809363109} is an apocalyptic number.

It is an amenable number.

1256809363109 is a deficient number, since it is larger than the sum of its proper divisors (26740624795).

1256809363109 is an equidigital number, since it uses as much as digits as its factorization.

1256809363109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26740624794.

The product of its (nonzero) digits is 2099520, while the sum is 53.

The spelling of 1256809363109 in words is "one trillion, two hundred fifty-six billion, eight hundred nine million, three hundred sixty-three thousand, one hundred nine".