256779139 has 4 divisors (see below), whose sum is σ = 257052960. Its totient is φ = 256505320.

The previous prime is 256779113. The next prime is 256779161. The reversal of 256779139 is 931977652.

256779139 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 a cyclic number.

It is not a de Polignac number, because 256779139 - 2¹¹ = 256777091 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 256779092 and 256779101.

It is not an unprimeable number, because it can be changed into a prime (256779109) 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, 135499 + ... + 137380.

It is an arithmetic number, because the mean of its divisors is an integer number (64263240).

Almost surely, 2^256779139 is an apocalyptic number.

256779139 is a deficient number, since it is larger than the sum of its proper divisors (273821).

256779139 is an equidigital number, since it uses as much as digits as its factorization.

256779139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273820.

The product of its digits is 714420, while the sum is 49.

The square root of 256779139 is about 16024.3295959613. The cubic root of 256779139 is about 635.6039382044.

The spelling of 256779139 in words is "two hundred fifty-six million, seven hundred seventy-nine thousand, one hundred thirty-nine".