204005551 has 2 divisors, whose sum is σ = 204005552. Its totient is φ = 204005550.

The previous prime is 204005509. The next prime is 204005573. The reversal of 204005551 is 155500402.

It is an a-pointer prime, because the next prime (204005573) can be obtained adding 204005551 to its sum of digits (22).

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 204005551 - 2¹⁷ = 203874479 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (204035551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102002775 + 102002776.

It is an arithmetic number, because the mean of its divisors is an integer number (102002776).

Almost surely, 2^204005551 is an apocalyptic number.

204005551 is a deficient number, since it is larger than the sum of its proper divisors (1).

204005551 is an equidigital number, since it uses as much as digits as its factorization.

204005551 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1000, while the sum is 22.

The square root of 204005551 is about 14283.0511796325. The cubic root of 204005551 is about 588.6818710899.

Adding to 204005551 its reverse (155500402), we get a palindrome (359505953).

The spelling of 204005551 in words is "two hundred four million, five thousand, five hundred fifty-one".