155209 has 2 divisors, whose sum is σ = 155210. Its totient is φ = 155208.

The previous prime is 155203. The next prime is 155219. The reversal of 155209 is 902551.

155209 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81225 + 73984 = 285^2 + 272^2 .

It is a cyclic number.

It is not a de Polignac number, because 155209 - 2³ = 155201 is a prime.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 155209.

It is not a weakly prime, because it can be changed into another prime (155201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77604 + 77605.

It is an arithmetic number, because the mean of its divisors is an integer number (77605).

2¹⁵⁵²⁰⁹ is an apocalyptic number.

It is an amenable number.

155209 is a deficient number, since it is larger than the sum of its proper divisors (1).

155209 is an equidigital number, since it uses as much as digits as its factorization.

155209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 450, while the sum is 22.

The square root of 155209 is about 393.9657345506. The cubic root of 155209 is about 53.7409864100.

The spelling of 155209 in words is "one hundred fifty-five thousand, two hundred nine".