1256260556305 has 4 divisors (see below), whose sum is σ = 1507512667572. Its totient is φ = 1005008445040.

The previous prime is 1256260556303. The next prime is 1256260556339. The reversal of 1256260556305 is 5036550626521.

It is a happy number.

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 260368329169 + 995892227136 = 510263^2 + 997944^2 .

It is not a de Polignac number, because 1256260556305 - 2¹ = 1256260556303 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1256260556303) 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, 125626055626 + ... + 125626055635.

It is an arithmetic number, because the mean of its divisors is an integer number (376878166893).

Almost surely, 2^{1256260556305} is an apocalyptic number.

It is an amenable number.

1256260556305 is a deficient number, since it is larger than the sum of its proper divisors (251252111267).

1256260556305 is an equidigital number, since it uses as much as digits as its factorization.

1256260556305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251252111266.

The product of its (nonzero) digits is 1620000, while the sum is 46.

The spelling of 1256260556305 in words is "one trillion, two hundred fifty-six billion, two hundred sixty million, five hundred fifty-six thousand, three hundred five".