125809549 has 2 divisors, whose sum is σ = 125809550. Its totient is φ = 125809548.

The previous prime is 125809547. The next prime is 125809561. The reversal of 125809549 is 945908521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 120890025 + 4919524 = 10995^2 + 2218^2 .

It is a cyclic number.

It is not a de Polignac number, because 125809549 - 2¹ = 125809547 is a prime.

Together with 125809547, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (125809547) 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, 62904774 + 62904775.

It is an arithmetic number, because the mean of its divisors is an integer number (62904775).

Almost surely, 2^125809549 is an apocalyptic number.

It is an amenable number.

125809549 is a deficient number, since it is larger than the sum of its proper divisors (1).

125809549 is an equidigital number, since it uses as much as digits as its factorization.

125809549 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 129600, while the sum is 43.

The square root of 125809549 is about 11216.4855904156. The cubic root of 125809549 is about 501.0770768117.

The spelling of 125809549 in words is "one hundred twenty-five million, eight hundred nine thousand, five hundred forty-nine".