1256805 has 24 divisors (see below), whose sum is σ = 2377440. Its totient is φ = 609120.

The previous prime is 1256797. The next prime is 1256809. The reversal of 1256805 is 5086521.

It is not a de Polignac number, because 1256805 - 2³ = 1256797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1256809) 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 23 ways as a sum of consecutive naturals, for example, 775 + ... + 1764.

It is an arithmetic number, because the mean of its divisors is an integer number (99060).

2^1256805 is an apocalyptic number.

1256805 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1256805 is a deficient number, since it is larger than the sum of its proper divisors (1120635).

1256805 is a wasteful number, since it uses less digits than its factorization.

1256805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2561 (or 2558 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 1256805 is about 1121.0731465877. The cubic root of 1256805 is about 107.9168598822.

The spelling of 1256805 in words is "one million, two hundred fifty-six thousand, eight hundred five".