256139 has 16 divisors (see below), whose sum is σ = 312480. Its totient is φ = 207360.

The previous prime is 256133. The next prime is 256147. The reversal of 256139 is 931652.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256139 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 (256133) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4169 + ... + 4229.

It is an arithmetic number, because the mean of its divisors is an integer number (19530).

2²⁵⁶¹³⁹ is an apocalyptic number.

256139 is a deficient number, since it is larger than the sum of its proper divisors (56341).

256139 is a wasteful number, since it uses less digits than its factorization.

256139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110.

The product of its digits is 1620, while the sum is 26.

The square root of 256139 is about 506.1017684221. The cubic root of 256139 is about 63.5075321216.

The spelling of 256139 in words is "two hundred fifty-six thousand, one hundred thirty-nine".