256366181 has 2 divisors, whose sum is σ = 256366182. Its totient is φ = 256366180.

The previous prime is 256366169. The next prime is 256366189. The reversal of 256366181 is 181663652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 250937281 + 5428900 = 15841^2 + 2330^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256366181 is a prime.

It is a super-2 number, since 2×256366181² = 131447237521049522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256366189) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128183090 + 128183091.

It is an arithmetic number, because the mean of its divisors is an integer number (128183091).

Almost surely, 2^256366181 is an apocalyptic number.

It is an amenable number.

256366181 is a deficient number, since it is larger than the sum of its proper divisors (1).

256366181 is an equidigital number, since it uses as much as digits as its factorization.

256366181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51840, while the sum is 38.

The square root of 256366181 is about 16011.4390671170. The cubic root of 256366181 is about 635.2630245234.

The spelling of 256366181 in words is "two hundred fifty-six million, three hundred sixty-six thousand, one hundred eighty-one".