25809834209 has 2 divisors, whose sum is σ = 25809834210. Its totient is φ = 25809834208.

The previous prime is 25809834199. The next prime is 25809834227. The reversal of 25809834209 is 90243890852.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20078890000 + 5730944209 = 141700^2 + 75703^2 .

It is a cyclic number.

It is not a de Polignac number, because 25809834209 - 2¹² = 25809830113 is a prime.

It is a super-2 number, since 2×25809834209² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (25809833209) 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 as a sum of consecutive naturals, namely, 12904917104 + 12904917105.

It is an arithmetic number, because the mean of its divisors is an integer number (12904917105).

Almost surely, 2^25809834209 is an apocalyptic number.

It is an amenable number.

25809834209 is a deficient number, since it is larger than the sum of its proper divisors (1).

25809834209 is an equidigital number, since it uses as much as digits as its factorization.

25809834209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1244160, while the sum is 50.

The spelling of 25809834209 in words is "twenty-five billion, eight hundred nine million, eight hundred thirty-four thousand, two hundred nine".