256911481 has 2 divisors, whose sum is σ = 256911482. Its totient is φ = 256911480.

The previous prime is 256911469. The next prime is 256911491. The reversal of 256911481 is 184119652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 138297600 + 118613881 = 11760^2 + 10891^2 .

It is a cyclic number.

It is not a de Polignac number, because 256911481 - 2¹³ = 256903289 is a prime.

It is a super-2 number, since 2×256911481² = 132007018139226722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 256911481.

It is not a weakly prime, because it can be changed into another prime (256911491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128455740 + 128455741.

It is an arithmetic number, because the mean of its divisors is an integer number (128455741).

Almost surely, 2^256911481 is an apocalyptic number.

It is an amenable number.

256911481 is a deficient number, since it is larger than the sum of its proper divisors (1).

256911481 is an equidigital number, since it uses as much as digits as its factorization.

256911481 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17280, while the sum is 37.

The square root of 256911481 is about 16028.4584723547. The cubic root of 256911481 is about 635.7131145829.

It can be divided in two parts, 25691 and 1481, that added together give a palindrome (27172).

The spelling of 256911481 in words is "two hundred fifty-six million, nine hundred eleven thousand, four hundred eighty-one".