55009 has 2 divisors, whose sum is σ = 55010. Its totient is φ = 55008.

The previous prime is 55001. The next prime is 55021. The reversal of 55009 is 90055.

55009 = T₁₉₀ + T₁₉₁ + T₁₉₂.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51984 + 3025 = 228^2 + 55^2 .

It is a cyclic number.

It is not a de Polignac number, because 55009 - 2³ = 55001 is a prime.

55009 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (55001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27504 + 27505.

It is an arithmetic number, because the mean of its divisors is an integer number (27505).

2⁵⁵⁰⁰⁹ is an apocalyptic number.

55009 is the 192-nd centered triangular number.

It is an amenable number.

55009 is a deficient number, since it is larger than the sum of its proper divisors (1).

55009 is an equidigital number, since it uses as much as digits as its factorization.

55009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 225, while the sum is 19.

The square root of 55009 is about 234.5399752707. The cubic root of 55009 is about 38.0315988322.

The spelling of 55009 in words is "fifty-five thousand, nine".