256798081 has 4 divisors (see below), whose sum is σ = 257919700. Its totient is φ = 255676464.

The previous prime is 256798067. The next prime is 256798097. The reversal of 256798081 is 180897652.

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

It can be written as a sum of positive squares in 2 ways, for example, as 249008400 + 7789681 = 15780^2 + 2791^2 .

It is a cyclic number.

It is not a de Polignac number, because 256798081 - 2⁵ = 256798049 is a prime.

It is a super-2 number, since 2×256798081² = 131890508810565122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256798781) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 560466 + ... + 560923.

It is an arithmetic number, because the mean of its divisors is an integer number (64479925).

Almost surely, 2^256798081 is an apocalyptic number.

It is an amenable number.

256798081 is a deficient number, since it is larger than the sum of its proper divisors (1121619).

256798081 is a wasteful number, since it uses less digits than its factorization.

256798081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1121618.

The product of its (nonzero) digits is 241920, while the sum is 46.

The square root of 256798081 is about 16024.9206238284. The cubic root of 256798081 is about 635.6195668283.

The spelling of 256798081 in words is "two hundred fifty-six million, seven hundred ninety-eight thousand, eighty-one".