205649729 has 2 divisors, whose sum is σ = 205649730. Its totient is φ = 205649728.

The previous prime is 205649723. The next prime is 205649767. The reversal of 205649729 is 927946502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 193210000 + 12439729 = 13900^2 + 3527^2 .

It is a cyclic number.

It is not a de Polignac number, because 205649729 - 2¹⁶ = 205584193 is a prime.

It is a super-2 number, since 2×205649729² = 84583622075546882, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 205649729.

It is not a weakly prime, because it can be changed into another prime (205649723) 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, 102824864 + 102824865.

It is an arithmetic number, because the mean of its divisors is an integer number (102824865).

Almost surely, 2^205649729 is an apocalyptic number.

It is an amenable number.

205649729 is a deficient number, since it is larger than the sum of its proper divisors (1).

205649729 is an equidigital number, since it uses as much as digits as its factorization.

205649729 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 272160, while the sum is 44.

The square root of 205649729 is about 14340.4926344948. The cubic root of 205649729 is about 590.2591306420.

The spelling of 205649729 in words is "two hundred five million, six hundred forty-nine thousand, seven hundred twenty-nine".