256181386 has 4 divisors (see below), whose sum is σ = 384272082. Its totient is φ = 128090692.

The previous prime is 256181371. The next prime is 256181411. The reversal of 256181386 is 683181652.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 229977225 + 26204161 = 15165^2 + 5119^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64045345 + ... + 64045348.

Almost surely, 2^256181386 is an apocalyptic number.

256181386 is a deficient number, since it is larger than the sum of its proper divisors (128090696).

256181386 is a wasteful number, since it uses less digits than its factorization.

256181386 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128090695.

The product of its digits is 69120, while the sum is 40.

The square root of 256181386 is about 16005.6673088003. The cubic root of 256181386 is about 635.1103501363.

The spelling of 256181386 in words is "two hundred fifty-six million, one hundred eighty-one thousand, three hundred eighty-six".