205478551 has 2 divisors, whose sum is σ = 205478552. Its totient is φ = 205478550.

The previous prime is 205478519. The next prime is 205478569. The reversal of 205478551 is 155874502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 205478551 - 2⁵ = 205478519 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 205478551.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205478051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102739275 + 102739276.

It is an arithmetic number, because the mean of its divisors is an integer number (102739276).

Almost surely, 2^205478551 is an apocalyptic number.

205478551 is a deficient number, since it is larger than the sum of its proper divisors (1).

205478551 is an equidigital number, since it uses as much as digits as its factorization.

205478551 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 56000, while the sum is 37.

The square root of 205478551 is about 14334.5230475241. The cubic root of 205478551 is about 590.0953125726.

The spelling of 205478551 in words is "two hundred five million, four hundred seventy-eight thousand, five hundred fifty-one".