125511509 has 2 divisors, whose sum is σ = 125511510. Its totient is φ = 125511508.

The previous prime is 125511499. The next prime is 125511517. The reversal of 125511509 is 905115521.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 104489284 + 21022225 = 10222^2 + 4585^2 .

It is a cyclic number.

It is not a de Polignac number, because 125511509 - 2¹⁶ = 125445973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (125511809) 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, 62755754 + 62755755.

It is an arithmetic number, because the mean of its divisors is an integer number (62755755).

Almost surely, 2^125511509 is an apocalyptic number.

It is an amenable number.

125511509 is a deficient number, since it is larger than the sum of its proper divisors (1).

125511509 is an equidigital number, since it uses as much as digits as its factorization.

125511509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2250, while the sum is 29.

The square root of 125511509 is about 11203.1919112367. The cubic root of 125511509 is about 500.6810838284.

The spelling of 125511509 in words is "one hundred twenty-five million, five hundred eleven thousand, five hundred nine".