256381121 has 2 divisors, whose sum is σ = 256381122. Its totient is φ = 256381120.

The previous prime is 256381057. The next prime is 256381187. The reversal of 256381121 is 121183652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 251698225 + 4682896 = 15865^2 + 2164^2 .

It is a cyclic number.

It is not a de Polignac number, because 256381121 - 2⁶ = 256381057 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (256381921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128190560 + 128190561.

It is an arithmetic number, because the mean of its divisors is an integer number (128190561).

Almost surely, 2^256381121 is an apocalyptic number.

It is an amenable number.

256381121 is a deficient number, since it is larger than the sum of its proper divisors (1).

256381121 is an equidigital number, since it uses as much as digits as its factorization.

256381121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2880, while the sum is 29.

The square root of 256381121 is about 16011.9056017702. The cubic root of 256381121 is about 635.2753644833.

The spelling of 256381121 in words is "two hundred fifty-six million, three hundred eighty-one thousand, one hundred twenty-one".