256020161 has 2 divisors, whose sum is σ = 256020162. Its totient is φ = 256020160.

The previous prime is 256020143. The next prime is 256020197. The reversal of 256020161 is 161020652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 254211136 + 1809025 = 15944^2 + 1345^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256020161 is a prime.

It is not a weakly prime, because it can be changed into another prime (256020101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128010080 + 128010081.

It is an arithmetic number, because the mean of its divisors is an integer number (128010081).

Almost surely, 2^256020161 is an apocalyptic number.

It is an amenable number.

256020161 is a deficient number, since it is larger than the sum of its proper divisors (1).

256020161 is an equidigital number, since it uses as much as digits as its factorization.

256020161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 256020161 is about 16000.6300188461. The cubic root of 256020161 is about 634.9770888875.

The spelling of 256020161 in words is "two hundred fifty-six million, twenty thousand, one hundred sixty-one".