256843381 has 4 divisors (see below), whose sum is σ = 263785132. Its totient is φ = 249901632.

The previous prime is 256843331. The next prime is 256843397. The reversal of 256843381 is 183348652.

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 183467025 + 73376356 = 13545^2 + 8566^2 .

It is a cyclic number.

It is not a de Polignac number, because 256843381 - 2⁷ = 256843253 is a prime.

It is a super-2 number, since 2×256843381² = 131937044727022322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256843331) 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, 3470820 + ... + 3470893.

It is an arithmetic number, because the mean of its divisors is an integer number (65946283).

Almost surely, 2^256843381 is an apocalyptic number.

It is an amenable number.

256843381 is a deficient number, since it is larger than the sum of its proper divisors (6941751).

256843381 is an equidigital number, since it uses as much as digits as its factorization.

256843381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6941750.

The product of its digits is 138240, while the sum is 40.

The square root of 256843381 is about 16026.3339850385. Note that the first 3 decimals coincide. The cubic root of 256843381 is about 635.6569397367.

The spelling of 256843381 in words is "two hundred fifty-six million, eight hundred forty-three thousand, three hundred eighty-one".