256317481 has 6 divisors (see below), whose sum is σ = 298165290. Its totient is φ = 219700656.

The previous prime is 256317473. The next prime is 256317511. The reversal of 256317481 is 184713652.

It can be written as a sum of positive squares in only one way, i.e., 203319081 + 52998400 = 14259^2 + 7280^2 .

It is not a de Polignac number, because 256317481 - 2³ = 256317473 is a prime.

It is a super-2 number, since 2×256317481² = 131397302132370722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 256317481.

It is not an unprimeable number, because it can be changed into a prime (256317401) 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 in 5 ways as a sum of consecutive naturals, for example, 2615436 + ... + 2615533.

It is an arithmetic number, because the mean of its divisors is an integer number (49694215).

Almost surely, 2^256317481 is an apocalyptic number.

It is an amenable number.

256317481 is a deficient number, since it is larger than the sum of its proper divisors (41847809).

256317481 is an equidigital number, since it uses as much as digits as its factorization.

256317481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5230983 (or 5230976 counting only the distinct ones).

The product of its digits is 40320, while the sum is 37.

The square root of 256317481 is about 16009.9182071615. The cubic root of 256317481 is about 635.2227965594. Note that the first 3 decimals are identical.

The spelling of 256317481 in words is "two hundred fifty-six million, three hundred seventeen thousand, four hundred eighty-one".