256173649 has 2 divisors, whose sum is σ = 256173650. Its totient is φ = 256173648.

The previous prime is 256173569. The next prime is 256173679. The reversal of 256173649 is 946371652.

256173649 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., 228977424 + 27196225 = 15132^2 + 5215^2 .

It is a cyclic number.

It is not a de Polignac number, because 256173649 - 2²¹ = 254076497 is a prime.

It is not a weakly prime, because it can be changed into another prime (256173679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128086824 + 128086825.

It is an arithmetic number, because the mean of its divisors is an integer number (128086825).

Almost surely, 2^256173649 is an apocalyptic number.

It is an amenable number.

256173649 is a deficient number, since it is larger than the sum of its proper divisors (1).

256173649 is an equidigital number, since it uses as much as digits as its factorization.

256173649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 272160, while the sum is 43.

The square root of 256173649 is about 16005.4256113357. The cubic root of 256173649 is about 635.1039563616.

The spelling of 256173649 in words is "two hundred fifty-six million, one hundred seventy-three thousand, six hundred forty-nine".