25545243105209 has 2 divisors, whose sum is σ = 25545243105210. Its totient is φ = 25545243105208.

The previous prime is 25545243105197. The next prime is 25545243105287. The reversal of 25545243105209 is 90250134254552.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25506994698025 + 38248407184 = 5050445^2 + 195572^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25545243105209 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (25545243105289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12772621552604 + 12772621552605.

It is an arithmetic number, because the mean of its divisors is an integer number (12772621552605).

Almost surely, 2^{25545243105209} is an apocalyptic number.

It is an amenable number.

25545243105209 is a deficient number, since it is larger than the sum of its proper divisors (1).

25545243105209 is an equidigital number, since it uses as much as digits as its factorization.

25545243105209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160000, while the sum is 47.

The spelling of 25545243105209 in words is "twenty-five trillion, five hundred forty-five billion, two hundred forty-three million, one hundred five thousand, two hundred nine".