256129 has 2 divisors, whose sum is σ = 256130. Its totient is φ = 256128.

The previous prime is 256121. The next prime is 256133. The reversal of 256129 is 921652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 223729 + 32400 = 473^2 + 180^2 .

It is a cyclic number.

It is not a de Polignac number, because 256129 - 2³ = 256121 is a prime.

It is an alternating number because its digits alternate between even and odd.

256129 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (256121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128064 + 128065.

It is an arithmetic number, because the mean of its divisors is an integer number (128065).

2²⁵⁶¹²⁹ is an apocalyptic number.

It is an amenable number.

256129 is a deficient number, since it is larger than the sum of its proper divisors (1).

256129 is an equidigital number, since it uses as much as digits as its factorization.

256129 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1080, while the sum is 25.

The square root of 256129 is about 506.0918888898. The cubic root of 256129 is about 63.5067056386.

The spelling of 256129 in words is "two hundred fifty-six thousand, one hundred twenty-nine".