125638009 has 24 divisors (see below), whose sum is σ = 152471808. Its totient is φ = 103108320.

The previous prime is 125637991. The next prime is 125638021. The reversal of 125638009 is 900836521.

It is not a de Polignac number, because 125638009 - 2⁷ = 125637881 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (125638049) 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 23 ways as a sum of consecutive naturals, for example, 162147 + ... + 162919.

It is an arithmetic number, because the mean of its divisors is an integer number (6352992).

Almost surely, 2^125638009 is an apocalyptic number.

It is an amenable number.

125638009 is a deficient number, since it is larger than the sum of its proper divisors (26833799).

125638009 is a wasteful number, since it uses less digits than its factorization.

125638009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 925 (or 918 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 125638009 is about 11208.8362018543. The cubic root of 125638009 is about 500.8492354483.

The spelling of 125638009 in words is "one hundred twenty-five million, six hundred thirty-eight thousand, nine".