125840840689 has 2 divisors, whose sum is σ = 125840840690. Its totient is φ = 125840840688.

The previous prime is 125840840683. The next prime is 125840840743. The reversal of 125840840689 is 986048048521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66015594225 + 59825246464 = 256935^2 + 244592^2 .

It is an emirp because it is prime and its reverse (986048048521) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-125840840689 is a prime.

It is not a weakly prime, because it can be changed into another prime (125840840683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62920420344 + 62920420345.

It is an arithmetic number, because the mean of its divisors is an integer number (62920420345).

Almost surely, 2^125840840689 is an apocalyptic number.

It is an amenable number.

125840840689 is a deficient number, since it is larger than the sum of its proper divisors (1).

125840840689 is an equidigital number, since it uses as much as digits as its factorization.

125840840689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4423680, while the sum is 55.

The spelling of 125840840689 in words is "one hundred twenty-five billion, eight hundred forty million, eight hundred forty thousand, six hundred eighty-nine".