25640305 has 8 divisors (see below), whose sum is σ = 31067712. Its totient is φ = 20312688.

The previous prime is 25640299. The next prime is 25640309. The reversal of 25640305 is 50304652.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 25640305 - 2⁹ = 25639793 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 25640305.

It is not an unprimeable number, because it can be changed into a prime (25640309) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24379 + ... + 25408.

It is an arithmetic number, because the mean of its divisors is an integer number (3883464).

Almost surely, 2^25640305 is an apocalyptic number.

It is an amenable number.

25640305 is a deficient number, since it is larger than the sum of its proper divisors (5427407).

25640305 is a wasteful number, since it uses less digits than its factorization.

25640305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49895.

The product of its (nonzero) digits is 3600, while the sum is 25.

The square root of 25640305 is about 5063.6256773186. The cubic root of 25640305 is about 294.8771105496.

Adding to 25640305 its reverse (50304652), we get a palindrome (75944957).

The spelling of 25640305 in words is "twenty-five million, six hundred forty thousand, three hundred five".