45209 has 4 divisors (see below), whose sum is σ = 46116. Its totient is φ = 44304.

The previous prime is 45197. The next prime is 45233. The reversal of 45209 is 90254.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90254 = 2 ⋅45127.

It can be written as a sum of positive squares in 2 ways, for example, as 15625 + 29584 = 125^2 + 172^2 .

It is a cyclic number.

It is not a de Polignac number, because 45209 - 2⁸ = 44953 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 45209.

It is not an unprimeable number, because it can be changed into a prime (45259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 374 + ... + 479.

It is an arithmetic number, because the mean of its divisors is an integer number (11529).

2⁴⁵²⁰⁹ is an apocalyptic number.

It is an amenable number.

45209 is a deficient number, since it is larger than the sum of its proper divisors (907).

45209 is an equidigital number, since it uses as much as digits as its factorization.

45209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 906.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 45209 is about 212.6240814207. The cubic root of 45209 is about 35.6239139917.

The spelling of 45209 in words is "forty-five thousand, two hundred nine".