25009 has 4 divisors (see below), whose sum is σ = 25380. Its totient is φ = 24640.

The previous prime is 24989. The next prime is 25013. The reversal of 25009 is 90052.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10609 + 14400 = 103^2 + 120^2 .

It is a cyclic number.

It is not a de Polignac number, because 25009 - 2⁵ = 24977 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 24983 and 25001.

It is not an unprimeable number, because it can be changed into a prime (25309) 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, 52 + ... + 229.

It is an arithmetic number, because the mean of its divisors is an integer number (6345).

2²⁵⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

25009 is a deficient number, since it is larger than the sum of its proper divisors (371).

25009 is an equidigital number, since it uses as much as digits as its factorization.

25009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370.

The product of its (nonzero) digits is 90, while the sum is 16.

The square root of 25009 is about 158.1423409464. The cubic root of 25009 is about 29.2436857824.

It can be divided in two parts, 2500 and 9, that multiplied together give a square (22500 = 150²).

The spelling of 25009 in words is "twenty-five thousand, nine".