256281689 has 2 divisors, whose sum is σ = 256281690. Its totient is φ = 256281688.

The previous prime is 256281643. The next prime is 256281691. The reversal of 256281689 is 986182652.

256281689 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 163968025 + 92313664 = 12805^2 + 9608^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256281689 is a prime.

Together with 256281691, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (256281089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128140844 + 128140845.

It is an arithmetic number, because the mean of its divisors is an integer number (128140845).

Almost surely, 2^256281689 is an apocalyptic number.

It is an amenable number.

256281689 is a deficient number, since it is larger than the sum of its proper divisors (1).

256281689 is an equidigital number, since it uses as much as digits as its factorization.

256281689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 414720, while the sum is 47.

The square root of 256281689 is about 16008.8003610514. The cubic root of 256281689 is about 635.1932278222.

The spelling of 256281689 in words is "two hundred fifty-six million, two hundred eighty-one thousand, six hundred eighty-nine".