205421747 has 2 divisors, whose sum is σ = 205421748. Its totient is φ = 205421746.

The previous prime is 205421737. The next prime is 205421771. The reversal of 205421747 is 747124502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 205421747 - 2⁴ = 205421731 is a prime.

It is not a weakly prime, because it can be changed into another prime (205421737) 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, 102710873 + 102710874.

It is an arithmetic number, because the mean of its divisors is an integer number (102710874).

Almost surely, 2^205421747 is an apocalyptic number.

205421747 is a deficient number, since it is larger than the sum of its proper divisors (1).

205421747 is an equidigital number, since it uses as much as digits as its factorization.

205421747 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15680, while the sum is 32.

The square root of 205421747 is about 14332.5415401456. The cubic root of 205421747 is about 590.0409308001.

The spelling of 205421747 in words is "two hundred five million, four hundred twenty-one thousand, seven hundred forty-seven".