256918647 has 4 divisors (see below), whose sum is σ = 342558200. Its totient is φ = 171279096.

The previous prime is 256918631. The next prime is 256918657. The reversal of 256918647 is 746819652.

256918647 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 256918647 - 2⁴ = 256918631 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 256918596 and 256918605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256918657) 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, 42819772 + ... + 42819777.

It is an arithmetic number, because the mean of its divisors is an integer number (85639550).

Almost surely, 2^256918647 is an apocalyptic number.

256918647 is a deficient number, since it is larger than the sum of its proper divisors (85639553).

256918647 is an equidigital number, since it uses as much as digits as its factorization.

256918647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85639552.

The product of its digits is 725760, while the sum is 48.

The square root of 256918647 is about 16028.6820106957. The cubic root of 256918647 is about 635.7190251503.

The spelling of 256918647 in words is "two hundred fifty-six million, nine hundred eighteen thousand, six hundred forty-seven".