25639945 has 16 divisors (see below), whose sum is σ = 32159232. Its totient is φ = 19601280.

The previous prime is 25639937. The next prime is 25639967. The reversal of 25639945 is 54993652.

It is not a de Polignac number, because 25639945 - 2³ = 25639937 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11869 + ... + 13861.

It is an arithmetic number, because the mean of its divisors is an integer number (2009952).

Almost surely, 2^25639945 is an apocalyptic number.

It is an amenable number.

25639945 is a deficient number, since it is larger than the sum of its proper divisors (6519287).

25639945 is a wasteful number, since it uses less digits than its factorization.

25639945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2112.

The product of its digits is 291600, while the sum is 43.

The square root of 25639945 is about 5063.5901295425. The cubic root of 25639945 is about 294.8757304795.

The spelling of 25639945 in words is "twenty-five million, six hundred thirty-nine thousand, nine hundred forty-five".