205912813 has 4 divisors (see below), whose sum is σ = 214865568. Its totient is φ = 196960060.

The previous prime is 205912801. The next prime is 205912831. The reversal of 205912813 is 318219502.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-205912813 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 (205912843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4476343 + ... + 4476388.

It is an arithmetic number, because the mean of its divisors is an integer number (53716392).

Almost surely, 2^205912813 is an apocalyptic number.

205912813 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

205912813 is a deficient number, since it is larger than the sum of its proper divisors (8952755).

205912813 is an equidigital number, since it uses as much as digits as its factorization.

205912813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8952754.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 205912813 is about 14349.6624698980. The cubic root of 205912813 is about 590.5107260156.

The spelling of 205912813 in words is "two hundred five million, nine hundred twelve thousand, eight hundred thirteen".