125509 has 2 divisors, whose sum is σ = 125510. Its totient is φ = 125508.

The previous prime is 125507. The next prime is 125527. The reversal of 125509 is 905521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 124609 + 900 = 353^2 + 30^2 .

It is a cyclic number.

It is not a de Polignac number, because 125509 - 2¹ = 125507 is a prime.

Together with 125507, it forms a pair of twin primes.

125509 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 125509.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (125507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62754 + 62755.

It is an arithmetic number, because the mean of its divisors is an integer number (62755).

2¹²⁵⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

125509 is a deficient number, since it is larger than the sum of its proper divisors (1).

125509 is an equidigital number, since it uses as much as digits as its factorization.

125509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 450, while the sum is 22.

The square root of 125509 is about 354.2724939930. The cubic root of 125509 is about 50.0677747568.

The spelling of 125509 in words is "one hundred twenty-five thousand, five hundred nine".