1255405 has 4 divisors (see below), whose sum is σ = 1506492. Its totient is φ = 1004320.

The previous prime is 1255393. The next prime is 1255421. The reversal of 1255405 is 5045521.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5045521 = 13 ⋅388117.

It can be written as a sum of positive squares in 2 ways, for example, as 777924 + 477481 = 882^2 + 691^2 .

It is not a de Polignac number, because 1255405 - 2¹⁹ = 731117 is a prime.

It is a Smith number, since the sum of its digits (22) 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 congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 125536 + ... + 125545.

It is an arithmetic number, because the mean of its divisors is an integer number (376623).

2^1255405 is an apocalyptic number.

It is an amenable number.

1255405 is a deficient number, since it is larger than the sum of its proper divisors (251087).

1255405 is an equidigital number, since it uses as much as digits as its factorization.

1255405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251086.

The product of its (nonzero) digits is 1000, while the sum is 22.

The square root of 1255405 is about 1120.4485708858. The cubic root of 1255405 is about 107.8767741787.

The spelling of 1255405 in words is "one million, two hundred fifty-five thousand, four hundred five".