1256681881 has 12 divisors (see below), whose sum is σ = 1574305572. Its totient is φ = 994297248.

The previous prime is 1256681879. The next prime is 1256681893. The reversal of 1256681881 is 1881866521.

It can be written as a sum of positive squares in 2 ways, for example, as 515971225 + 740710656 = 22715^2 + 27216^2 .

It is not a de Polignac number, because 1256681881 - 2¹ = 1256681879 is a prime.

It is a super-2 number, since 2×1256681881² = 3158498700067396322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1256681281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 985770 + ... + 987043.

It is an arithmetic number, because the mean of its divisors is an integer number (131192131).

Almost surely, 2^1256681881 is an apocalyptic number.

It is an amenable number.

1256681881 is a deficient number, since it is larger than the sum of its proper divisors (317623691).

1256681881 is a wasteful number, since it uses less digits than its factorization.

1256681881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1972840 (or 1972833 counting only the distinct ones).

The product of its digits is 184320, while the sum is 46.

The square root of 1256681881 is about 35449.7091807535. The cubic root of 1256681881 is about 1079.1333585369.

The spelling of 1256681881 in words is "one billion, two hundred fifty-six million, six hundred eighty-one thousand, eight hundred eighty-one".