1256839 has 4 divisors (see below), whose sum is σ = 1259224. Its totient is φ = 1254456.

The previous prime is 1256837. The next prime is 1256863. The reversal of 1256839 is 9386521.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9386521 = 31 ⋅302791.

It is a cyclic number.

It is not a de Polignac number, because 1256839 - 2¹ = 1256837 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 (1256837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12 + ... + 1585.

It is an arithmetic number, because the mean of its divisors is an integer number (314806).

2^1256839 is an apocalyptic number.

1256839 is a deficient number, since it is larger than the sum of its proper divisors (2385).

1256839 is an equidigital number, since it uses as much as digits as its factorization.

1256839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2384.

The product of its digits is 12960, while the sum is 34.

The square root of 1256839 is about 1121.0883105269. The cubic root of 1256839 is about 107.9178330218.

The spelling of 1256839 in words is "one million, two hundred fifty-six thousand, eight hundred thirty-nine".