125138681 has 2 divisors, whose sum is σ = 125138682. Its totient is φ = 125138680.

The previous prime is 125138669. The next prime is 125138687. The reversal of 125138681 is 186831521.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 105247081 + 19891600 = 10259^2 + 4460^2 .

It is an emirp because it is prime and its reverse (186831521) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 125138681 - 2²² = 120944377 is a prime.

It is a super-2 number, since 2×125138681² = 31319378964839522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (125138687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62569340 + 62569341.

It is an arithmetic number, because the mean of its divisors is an integer number (62569341).

Almost surely, 2^125138681 is an apocalyptic number.

It is an amenable number.

125138681 is a deficient number, since it is larger than the sum of its proper divisors (1).

125138681 is an equidigital number, since it uses as much as digits as its factorization.

125138681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11520, while the sum is 35.

The square root of 125138681 is about 11186.5401711164. The cubic root of 125138681 is about 500.1848396602.

The spelling of 125138681 in words is "one hundred twenty-five million, one hundred thirty-eight thousand, six hundred eighty-one".