25643609 has 4 divisors (see below), whose sum is σ = 26240016. Its totient is φ = 25047204.

The previous prime is 25643593. The next prime is 25643621. The reversal of 25643609 is 90634652.

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 not a de Polignac number, because 25643609 - 2⁴ = 25643593 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (25643669) 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, 298139 + ... + 298224.

It is an arithmetic number, because the mean of its divisors is an integer number (6560004).

Almost surely, 2^25643609 is an apocalyptic number.

It is an amenable number.

25643609 is a deficient number, since it is larger than the sum of its proper divisors (596407).

25643609 is an equidigital number, since it uses as much as digits as its factorization.

25643609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 596406.

The product of its (nonzero) digits is 38880, while the sum is 35.

The square root of 25643609 is about 5063.9519152535. The cubic root of 25643609 is about 294.8897759233.

The spelling of 25643609 in words is "twenty-five million, six hundred forty-three thousand, six hundred nine".