125661609 has 12 divisors (see below), whose sum is σ = 185732976. Its totient is φ = 81825912.

The previous prime is 125661607. The next prime is 125661623. The reversal of 125661609 is 906166521.

It is not a de Polignac number, because 125661609 - 2¹ = 125661607 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (125661607) 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 in 11 ways as a sum of consecutive naturals, for example, 161967 + ... + 162740.

It is an arithmetic number, because the mean of its divisors is an integer number (15477748).

Almost surely, 2^125661609 is an apocalyptic number.

It is an amenable number.

125661609 is a deficient number, since it is larger than the sum of its proper divisors (60071367).

125661609 is a wasteful number, since it uses less digits than its factorization.

125661609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 324756 (or 324753 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The square root of 125661609 is about 11209.8888932942. Note that the first 4 decimals coincide. The cubic root of 125661609 is about 500.8805935329.

The spelling of 125661609 in words is "one hundred twenty-five million, six hundred sixty-one thousand, six hundred nine".