204121721 has 2 divisors, whose sum is σ = 204121722. Its totient is φ = 204121720.

The previous prime is 204121699. The next prime is 204121727. The reversal of 204121721 is 127121402.

204121721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 200647225 + 3474496 = 14165^2 + 1864^2 .

It is a cyclic number.

It is not a de Polignac number, because 204121721 - 2²² = 199927417 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 204121693 and 204121702.

It is not a weakly prime, because it can be changed into another prime (204121727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102060860 + 102060861.

It is an arithmetic number, because the mean of its divisors is an integer number (102060861).

Almost surely, 2^204121721 is an apocalyptic number.

It is an amenable number.

204121721 is a deficient number, since it is larger than the sum of its proper divisors (1).

204121721 is an equidigital number, since it uses as much as digits as its factorization.

204121721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 224, while the sum is 20.

The square root of 204121721 is about 14287.1173089605. The cubic root of 204121721 is about 588.7935905927.

The spelling of 204121721 in words is "two hundred four million, one hundred twenty-one thousand, seven hundred twenty-one".