25518521117 has 2 divisors, whose sum is σ = 25518521118. Its totient is φ = 25518521116.

The previous prime is 25518521081. The next prime is 25518521123. The reversal of 25518521117 is 71112581552.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14433379321 + 11085141796 = 120139^2 + 105286^2 .

It is a cyclic number.

It is not a de Polignac number, because 25518521117 - 2¹⁴ = 25518504733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25518521417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12759260558 + 12759260559.

It is an arithmetic number, because the mean of its divisors is an integer number (12759260559).

Almost surely, 2^25518521117 is an apocalyptic number.

It is an amenable number.

25518521117 is a deficient number, since it is larger than the sum of its proper divisors (1).

25518521117 is an equidigital number, since it uses as much as digits as its factorization.

25518521117 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 28000, while the sum is 38.

The spelling of 25518521117 in words is "twenty-five billion, five hundred eighteen million, five hundred twenty-one thousand, one hundred seventeen".