205691489 has 4 divisors (see below), whose sum is σ = 210475056. Its totient is φ = 200907924.

The previous prime is 205691467. The next prime is 205691491. The reversal of 205691489 is 984196502.

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 a de Polignac number, because none of the positive numbers 2^k-205691489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (205691429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2391719 + ... + 2391804.

It is an arithmetic number, because the mean of its divisors is an integer number (52618764).

Almost surely, 2^205691489 is an apocalyptic number.

It is an amenable number.

205691489 is a deficient number, since it is larger than the sum of its proper divisors (4783567).

205691489 is an equidigital number, since it uses as much as digits as its factorization.

205691489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4783566.

The product of its (nonzero) digits is 155520, while the sum is 44.

The square root of 205691489 is about 14341.9485775121. The cubic root of 205691489 is about 590.2990813438.

The spelling of 205691489 in words is "two hundred five million, six hundred ninety-one thousand, four hundred eighty-nine".