256001609 has 2 divisors, whose sum is σ = 256001610. Its totient is φ = 256001608.

The previous prime is 256001597. The next prime is 256001639. The reversal of 256001609 is 906100652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 177289225 + 78712384 = 13315^2 + 8872^2 .

It is a cyclic number.

It is not a de Polignac number, because 256001609 - 2⁴ = 256001593 is a prime.

It is not a weakly prime, because it can be changed into another prime (256001639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128000804 + 128000805.

It is an arithmetic number, because the mean of its divisors is an integer number (128000805).

Almost surely, 2^256001609 is an apocalyptic number.

It is an amenable number.

256001609 is a deficient number, since it is larger than the sum of its proper divisors (1).

256001609 is an equidigital number, since it uses as much as digits as its factorization.

256001609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 256001609 is about 16000.0502811710. The cubic root of 256001609 is about 634.9617510596.

The spelling of 256001609 in words is "two hundred fifty-six million, one thousand, six hundred nine".