25617665849 has 2 divisors, whose sum is σ = 25617665850. Its totient is φ = 25617665848.

The previous prime is 25617665837. The next prime is 25617665851. The reversal of 25617665849 is 94856671652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20211740224 + 5405925625 = 142168^2 + 73525^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25617665849 is a prime.

Together with 25617665851, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (25617665809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12808832924 + 12808832925.

It is an arithmetic number, because the mean of its divisors is an integer number (12808832925).

Almost surely, 2^25617665849 is an apocalyptic number.

It is an amenable number.

25617665849 is a deficient number, since it is larger than the sum of its proper divisors (1).

25617665849 is an equidigital number, since it uses as much as digits as its factorization.

25617665849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21772800, while the sum is 59.

The spelling of 25617665849 in words is "twenty-five billion, six hundred seventeen million, six hundred sixty-five thousand, eight hundred forty-nine".