125508502561 has 16 divisors (see below), whose sum is σ = 135587203024. Its totient is φ = 115490893824.

The previous prime is 125508502489. The next prime is 125508502573. The reversal of 125508502561 is 165205805521.

It can be written as a sum of positive squares in 8 ways, for example, as 96904336 + 125411598225 = 9844^2 + 354135^2 .

It is a cyclic number.

It is not a de Polignac number, because 125508502561 - 2⁷ = 125508502433 is a prime.

It is not an unprimeable number, because it can be changed into a prime (125508502261) 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 15 ways as a sum of consecutive naturals, for example, 6626641 + ... + 6645553.

It is an arithmetic number, because the mean of its divisors is an integer number (8474200189).

Almost surely, 2^125508502561 is an apocalyptic number.

It is an amenable number.

125508502561 is a deficient number, since it is larger than the sum of its proper divisors (10078700463).

125508502561 is a wasteful number, since it uses less digits than its factorization.

125508502561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20500.

The product of its (nonzero) digits is 120000, while the sum is 40.

The spelling of 125508502561 in words is "one hundred twenty-five billion, five hundred eight million, five hundred two thousand, five hundred sixty-one".