205006643 has 4 divisors (see below), whose sum is σ = 205241280. Its totient is φ = 204772008.

The previous prime is 205006639. The next prime is 205006657. The reversal of 205006643 is 346600502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 346600502 = 2 ⋅173300251.

It is a cyclic number.

It is not a de Polignac number, because 205006643 - 2² = 205006639 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (205006673) by changing a digit.

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, 116003 + ... + 117756.

It is an arithmetic number, because the mean of its divisors is an integer number (51310320).

Almost surely, 2^205006643 is an apocalyptic number.

205006643 is a deficient number, since it is larger than the sum of its proper divisors (234637).

205006643 is an equidigital number, since it uses as much as digits as its factorization.

205006643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234636.

The product of its (nonzero) digits is 4320, while the sum is 26.

The square root of 205006643 is about 14318.0530450198. The cubic root of 205006643 is about 589.6432229650.

The spelling of 205006643 in words is "two hundred five million, six thousand, six hundred forty-three".