25785509 has 4 divisors (see below), whose sum is σ = 26385216. Its totient is φ = 25185804.

The previous prime is 25785499. The next prime is 25785511. The reversal of 25785509 is 90558752.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25785509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25785569) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 299789 + ... + 299874.

It is an arithmetic number, because the mean of its divisors is an integer number (6596304).

Almost surely, 2^25785509 is an apocalyptic number.

It is an amenable number.

25785509 is a deficient number, since it is larger than the sum of its proper divisors (599707).

25785509 is an equidigital number, since it uses as much as digits as its factorization.

25785509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 599706.

The product of its (nonzero) digits is 126000, while the sum is 41.

The square root of 25785509 is about 5077.9433829061. The cubic root of 25785509 is about 295.4327040810.

The spelling of 25785509 in words is "twenty-five million, seven hundred eighty-five thousand, five hundred nine".