25809813 has 8 divisors (see below), whose sum is σ = 38236800. Its totient is φ = 17206524.

The previous prime is 25809811. The next prime is 25809821. The reversal of 25809813 is 31890852.

It is not a de Polignac number, because 25809813 - 2¹ = 25809811 is a prime.

It is a super-2 number, since 2×25809813² = 1332292894189938, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25809811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 477933 + ... + 477986.

It is an arithmetic number, because the mean of its divisors is an integer number (4779600).

Almost surely, 2^25809813 is an apocalyptic number.

It is an amenable number.

25809813 is a deficient number, since it is larger than the sum of its proper divisors (12426987).

25809813 is an equidigital number, since it uses as much as digits as its factorization.

25809813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 955928 (or 955922 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 25809813 is about 5080.3359140907. The cubic root of 25809813 is about 295.5254944635.

The spelling of 25809813 in words is "twenty-five million, eight hundred nine thousand, eight hundred thirteen".