125765021 has 2 divisors, whose sum is σ = 125765022. Its totient is φ = 125765020.

The previous prime is 125765011. The next prime is 125765023. The reversal of 125765021 is 120567521.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 123765625 + 1999396 = 11125^2 + 1414^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-125765021 is a prime.

It is a Sophie Germain prime.

Together with 125765023, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (125765023) 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 as a sum of consecutive naturals, namely, 62882510 + 62882511.

It is an arithmetic number, because the mean of its divisors is an integer number (62882511).

Almost surely, 2^125765021 is an apocalyptic number.

It is an amenable number.

125765021 is a deficient number, since it is larger than the sum of its proper divisors (1).

125765021 is an equidigital number, since it uses as much as digits as its factorization.

125765021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4200, while the sum is 29.

The square root of 125765021 is about 11214.5004792902. The cubic root of 125765021 is about 501.0179541323.

The spelling of 125765021 in words is "one hundred twenty-five million, seven hundred sixty-five thousand, twenty-one".