204921035555809 has 2 divisors, whose sum is σ = 204921035555810. Its totient is φ = 204921035555808.

The previous prime is 204921035555779. The next prime is 204921035555833. The reversal of 204921035555809 is 908555530129402.

204921035555809 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 202517518648225 + 2403516907584 = 14230865^2 + 1550328^2 .

It is a cyclic number.

It is not a de Polignac number, because 204921035555809 - 2⁵ = 204921035555777 is a prime.

It is not a weakly prime, because it can be changed into another prime (204921035555869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102460517777904 + 102460517777905.

It is an arithmetic number, because the mean of its divisors is an integer number (102460517777905).

Almost surely, 2^{204921035555809} is an apocalyptic number.

It is an amenable number.

204921035555809 is a deficient number, since it is larger than the sum of its proper divisors (1).

204921035555809 is an equidigital number, since it uses as much as digits as its factorization.

204921035555809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19440000, while the sum is 58.

The spelling of 204921035555809 in words is "two hundred four trillion, nine hundred twenty-one billion, thirty-five million, five hundred fifty-five thousand, eight hundred nine".