125765209 has 2 divisors, whose sum is σ = 125765210. Its totient is φ = 125765208.

The previous prime is 125765191. The next prime is 125765243. The reversal of 125765209 is 902567521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 92160000 + 33605209 = 9600^2 + 5797^2 .

It is an emirp because it is prime and its reverse (902567521) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 125765209 - 2⁵ = 125765177 is a prime.

It is not a weakly prime, because it can be changed into another prime (125765249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62882604 + 62882605.

It is an arithmetic number, because the mean of its divisors is an integer number (62882605).

Almost surely, 2^125765209 is an apocalyptic number.

It is an amenable number.

125765209 is a deficient number, since it is larger than the sum of its proper divisors (1).

125765209 is an equidigital number, since it uses as much as digits as its factorization.

125765209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 37800, while the sum is 37.

The square root of 125765209 is about 11214.5088612921. The cubic root of 125765209 is about 501.0182037813.

It can be divided in two parts, 1257 and 65209, that added together give a palindrome (66466).

The spelling of 125765209 in words is "one hundred twenty-five million, seven hundred sixty-five thousand, two hundred nine".