204243989 has 2 divisors, whose sum is σ = 204243990. Its totient is φ = 204243988.

The previous prime is 204243961. The next prime is 204244009. The reversal of 204243989 is 989342402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 128640964 + 75603025 = 11342^2 + 8695^2 .

It is a cyclic number.

It is not a de Polignac number, because 204243989 - 2⁸ = 204243733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (204246989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102121994 + 102121995.

It is an arithmetic number, because the mean of its divisors is an integer number (102121995).

Almost surely, 2^204243989 is an apocalyptic number.

It is an amenable number.

204243989 is a deficient number, since it is larger than the sum of its proper divisors (1).

204243989 is an equidigital number, since it uses as much as digits as its factorization.

204243989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 124416, while the sum is 41.

The square root of 204243989 is about 14291.3956281393. The cubic root of 204243989 is about 588.9111287053.

The spelling of 204243989 in words is "two hundred four million, two hundred forty-three thousand, nine hundred eighty-nine".