204039721 has 2 divisors, whose sum is σ = 204039722. Its totient is φ = 204039720.

The previous prime is 204039707. The next prime is 204039749. The reversal of 204039721 is 127930402.

It is an a-pointer prime, because the next prime (204039749) can be obtained adding 204039721 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 198105625 + 5934096 = 14075^2 + 2436^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-204039721 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 204039721.

It is not a weakly prime, because it can be changed into another prime (204039221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102019860 + 102019861.

It is an arithmetic number, because the mean of its divisors is an integer number (102019861).

Almost surely, 2^204039721 is an apocalyptic number.

It is an amenable number.

204039721 is a deficient number, since it is larger than the sum of its proper divisors (1).

204039721 is an equidigital number, since it uses as much as digits as its factorization.

204039721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 204039721 is about 14284.2473025358. The cubic root of 204039721 is about 588.7147364319.

The spelling of 204039721 in words is "two hundred four million, thirty-nine thousand, seven hundred twenty-one".