1205813 has 4 divisors (see below), whose sum is σ = 1378080. Its totient is φ = 1033548.

The previous prime is 1205779. The next prime is 1205819. The reversal of 1205813 is 3185021.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 3185021 = 7 ⋅455003.

It is a cyclic number.

It is not a de Polignac number, because 1205813 - 2⁶ = 1205749 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1205819) 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, 86123 + ... + 86136.

It is an arithmetic number, because the mean of its divisors is an integer number (344520).

2^1205813 is an apocalyptic number.

It is an amenable number.

1205813 is a deficient number, since it is larger than the sum of its proper divisors (172267).

1205813 is an equidigital number, since it uses as much as digits as its factorization.

1205813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172266.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 1205813 is about 1098.0951689175. The cubic root of 1205813 is about 106.4371704322.

The spelling of 1205813 in words is "one million, two hundred five thousand, eight hundred thirteen".