204142021 has 2 divisors, whose sum is σ = 204142022. Its totient is φ = 204142020.

The previous prime is 204142019. The next prime is 204142033. The reversal of 204142021 is 120241402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 203062500 + 1079521 = 14250^2 + 1039^2 .

It is a cyclic number.

It is not a de Polignac number, because 204142021 - 2¹ = 204142019 is a prime.

Together with 204142019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 204141986 and 204142004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (204142621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102071010 + 102071011.

It is an arithmetic number, because the mean of its divisors is an integer number (102071011).

Almost surely, 2^204142021 is an apocalyptic number.

It is an amenable number.

204142021 is a deficient number, since it is larger than the sum of its proper divisors (1).

204142021 is an equidigital number, since it uses as much as digits as its factorization.

204142021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 204142021 is about 14287.8277215258. The cubic root of 204142021 is about 588.8131085444.

Adding to 204142021 its reverse (120241402), we get a palindrome (324383423).

The spelling of 204142021 in words is "two hundred four million, one hundred forty-two thousand, twenty-one".