205404989 has 4 divisors (see below), whose sum is σ = 205459200. Its totient is φ = 205350780.

The previous prime is 205404971. The next prime is 205405001. The reversal of 205404989 is 989404502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 205404989 - 2¹² = 205400893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205404929) 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 in 3 ways as a sum of consecutive naturals, for example, 20957 + ... + 29154.

It is an arithmetic number, because the mean of its divisors is an integer number (51364800).

Almost surely, 2^205404989 is an apocalyptic number.

It is an amenable number.

205404989 is a deficient number, since it is larger than the sum of its proper divisors (54211).

205404989 is an equidigital number, since it uses as much as digits as its factorization.

205404989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54210.

The product of its (nonzero) digits is 103680, while the sum is 41.

The square root of 205404989 is about 14331.9569145319. The cubic root of 205404989 is about 590.0248854772.

The spelling of 205404989 in words is "two hundred five million, four hundred four thousand, nine hundred eighty-nine".