1256005 has 4 divisors (see below), whose sum is σ = 1507212. Its totient is φ = 1004800.

The previous prime is 1255997. The next prime is 1256009. The reversal of 1256005 is 5006521.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 519841 + 736164 = 721^2 + 858^2 .

It is not a de Polignac number, because 1256005 - 2³ = 1255997 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 (1256009) 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, 125596 + ... + 125605.

It is an arithmetic number, because the mean of its divisors is an integer number (376803).

2^1256005 is an apocalyptic number.

It is an amenable number.

1256005 is a deficient number, since it is larger than the sum of its proper divisors (251207).

1256005 is an equidigital number, since it uses as much as digits as its factorization.

1256005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251206.

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 1256005 is about 1120.7162888082. The cubic root of 1256005 is about 107.8939574132.

The spelling of 1256005 in words is "one million, two hundred fifty-six thousand, five".