125319809 has 2 divisors, whose sum is σ = 125319810. Its totient is φ = 125319808.

The previous prime is 125319793. The next prime is 125319811. The reversal of 125319809 is 908913521.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80496784 + 44823025 = 8972^2 + 6695^2 .

It is a cyclic number.

It is not a de Polignac number, because 125319809 - 2⁴ = 125319793 is a prime.

Together with 125319811, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (125319109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62659904 + 62659905.

It is an arithmetic number, because the mean of its divisors is an integer number (62659905).

Almost surely, 2^125319809 is an apocalyptic number.

It is an amenable number.

125319809 is a deficient number, since it is larger than the sum of its proper divisors (1).

125319809 is an equidigital number, since it uses as much as digits as its factorization.

125319809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 19440, while the sum is 38.

The square root of 125319809 is about 11194.6330444548. The cubic root of 125319809 is about 500.4260488616.

The spelling of 125319809 in words is "one hundred twenty-five million, three hundred nineteen thousand, eight hundred nine".