256117655 has 4 divisors (see below), whose sum is σ = 307341192. Its totient is φ = 204894120.

The previous prime is 256117651. The next prime is 256117669. The reversal of 256117655 is 556711652.

256117655 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 256117655 - 2² = 256117651 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256117651) 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, 25611761 + ... + 25611770.

It is an arithmetic number, because the mean of its divisors is an integer number (76835298).

Almost surely, 2^256117655 is an apocalyptic number.

256117655 is a deficient number, since it is larger than the sum of its proper divisors (51223537).

256117655 is an equidigital number, since it uses as much as digits as its factorization.

256117655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51223536.

The product of its digits is 63000, while the sum is 38.

The square root of 256117655 is about 16003.6762964014. The cubic root of 256117655 is about 635.0576796759.

The spelling of 256117655 in words is "two hundred fifty-six million, one hundred seventeen thousand, six hundred fifty-five".