204721 has 8 divisors (see below), whose sum is σ = 229824. Its totient is φ = 180720.

The previous prime is 204719. The next prime is 204733. The reversal of 204721 is 127402.

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 204721 - 2¹ = 204719 is a prime.

It is a Duffinian number.

204721 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 204695 and 204704.

It is not an unprimeable number, because it can be changed into a prime (204751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 156 + ... + 658.

It is an arithmetic number, because the mean of its divisors is an integer number (28728).

2²⁰⁴⁷²¹ is an apocalyptic number.

It is an amenable number.

204721 is a deficient number, since it is larger than the sum of its proper divisors (25103).

204721 is a wasteful number, since it uses less digits than its factorization.

204721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 551.

The product of its (nonzero) digits is 112, while the sum is 16.

The square root of 204721 is about 452.4610480472. The cubic root of 204721 is about 58.9369238762.

The spelling of 204721 in words is "two hundred four thousand, seven hundred twenty-one", and thus it is an iban number.