125856634109 has 2 divisors, whose sum is σ = 125856634110. Its totient is φ = 125856634108.

The previous prime is 125856634097. The next prime is 125856634139. The reversal of 125856634109 is 901436658521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 109478265625 + 16378368484 = 330875^2 + 127978^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-125856634109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (125856634139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62928317054 + 62928317055.

It is an arithmetic number, because the mean of its divisors is an integer number (62928317055).

Almost surely, 2^125856634109 is an apocalyptic number.

It is an amenable number.

125856634109 is a deficient number, since it is larger than the sum of its proper divisors (1).

125856634109 is an equidigital number, since it uses as much as digits as its factorization.

125856634109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1555200, while the sum is 50.

The spelling of 125856634109 in words is "one hundred twenty-five billion, eight hundred fifty-six million, six hundred thirty-four thousand, one hundred nine".