551909 has 2 divisors, whose sum is σ = 551910. Its totient is φ = 551908.

The previous prime is 551861. The next prime is 551911. The reversal of 551909 is 909155.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 521284 + 30625 = 722^2 + 175^2 .

It is a cyclic number.

It is not a de Polignac number, because 551909 - 2⁸ = 551653 is a prime.

Together with 551911, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (551959) 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 as a sum of consecutive naturals, namely, 275954 + 275955.

It is an arithmetic number, because the mean of its divisors is an integer number (275955).

2⁵⁵¹⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

551909 is a deficient number, since it is larger than the sum of its proper divisors (1).

551909 is an equidigital number, since it uses as much as digits as its factorization.

551909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2025, while the sum is 29.

The square root of 551909 is about 742.9057813747. The cubic root of 551909 is about 82.0268105867.

The spelling of 551909 in words is "five hundred fifty-one thousand, nine hundred nine".