1205605 has 8 divisors (see below), whose sum is σ = 1482264. Its totient is φ = 940800.

The previous prime is 1205563. The next prime is 1205609. The reversal of 1205605 is 5065021.

It is a happy number.

It is a Cunningham number, because it is equal to 1098²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 58564 + 1147041 = 242^2 + 1071^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1205605 - 2⁹ = 1205093 is a prime.

It is a Duffinian number.

1205605 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1205609) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2736 + ... + 3145.

It is an arithmetic number, because the mean of its divisors is an integer number (185283).

2^1205605 is an apocalyptic number.

It is an amenable number.

1205605 is a deficient number, since it is larger than the sum of its proper divisors (276659).

1205605 is an equidigital number, since it uses as much as digits as its factorization.

1205605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5927.

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

The square root of 1205605 is about 1098.0004553733. Note that the first 3 decimals coincide. The cubic root of 1205605 is about 106.4310500237.

The spelling of 1205605 in words is "one million, two hundred five thousand, six hundred five".