125815309 has 2 divisors, whose sum is σ = 125815310. Its totient is φ = 125815308.

The previous prime is 125815303. The next prime is 125815343. The reversal of 125815309 is 903518521.

It is an a-pointer prime, because the next prime (125815343) can be obtained adding 125815309 to its sum of digits (34).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 70610409 + 55204900 = 8403^2 + 7430^2 .

It is an emirp because it is prime and its reverse (903518521) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 125815309 - 2¹³ = 125807117 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (125815303) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62907654 + 62907655.

It is an arithmetic number, because the mean of its divisors is an integer number (62907655).

Almost surely, 2^125815309 is an apocalyptic number.

It is an amenable number.

125815309 is a deficient number, since it is larger than the sum of its proper divisors (1).

125815309 is an equidigital number, since it uses as much as digits as its factorization.

125815309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10800, while the sum is 34.

The square root of 125815309 is about 11216.7423523945. The cubic root of 125815309 is about 501.0847237138.

The spelling of 125815309 in words is "one hundred twenty-five million, eight hundred fifteen thousand, three hundred nine".