25640839 has 4 divisors (see below), whose sum is σ = 29303824. Its totient is φ = 21977856.

The previous prime is 25640831. The next prime is 25640863. The reversal of 25640839 is 93804652.

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

It is a cyclic number.

It is not a de Polignac number, because 25640839 - 2³ = 25640831 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a junction number, because it is equal to n+sod(n) for n = 25640798 and 25640807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25640831) 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, 1831482 + ... + 1831495.

It is an arithmetic number, because the mean of its divisors is an integer number (7325956).

Almost surely, 2^25640839 is an apocalyptic number.

25640839 is a deficient number, since it is larger than the sum of its proper divisors (3662985).

25640839 is an equidigital number, since it uses as much as digits as its factorization.

25640839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3662984.

The product of its (nonzero) digits is 51840, while the sum is 37.

The square root of 25640839 is about 5063.6784060602. The cubic root of 25640839 is about 294.8791576299.

The spelling of 25640839 in words is "twenty-five million, six hundred forty thousand, eight hundred thirty-nine".