813605 has 8 divisors (see below), whose sum is σ = 1051512. Its totient is φ = 600768.

The previous prime is 813601. The next prime is 813613. The reversal of 813605 is 506318.

It is a Cunningham number, because it is equal to 902²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 119716 + 693889 = 346^2 + 833^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 813605 - 2² = 813601 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 813605.

It is not an unprimeable number, because it can be changed into a prime (813601) 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, 6194 + ... + 6323.

It is an arithmetic number, because the mean of its divisors is an integer number (131439).

2⁸¹³⁶⁰⁵ is an apocalyptic number.

It is an amenable number.

813605 is a deficient number, since it is larger than the sum of its proper divisors (237907).

813605 is a wasteful number, since it uses less digits than its factorization.

813605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12535.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 813605 is about 902.0005543236. Note that the first 3 decimals coincide. The cubic root of 813605 is about 93.3550615512.

The spelling of 813605 in words is "eight hundred thirteen thousand, six hundred five".