126189509 has 2 divisors, whose sum is σ = 126189510. Its totient is φ = 126189508.

The previous prime is 126189493. The next prime is 126189529. The reversal of 126189509 is 905981621.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 115627009 + 10562500 = 10753^2 + 3250^2 .

It is an emirp because it is prime and its reverse (905981621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 126189509 - 2⁴ = 126189493 is a prime.

It is a super-2 number, since 2×126189509² = 31847584363322162, which contains 22 as substring.

It is a Sophie Germain 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 (126189529) 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, 63094754 + 63094755.

It is an arithmetic number, because the mean of its divisors is an integer number (63094755).

Almost surely, 2^126189509 is an apocalyptic number.

It is an amenable number.

126189509 is a deficient number, since it is larger than the sum of its proper divisors (1).

126189509 is an equidigital number, since it uses as much as digits as its factorization.

126189509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 38880, while the sum is 41.

The square root of 126189509 is about 11233.4103904380. The cubic root of 126189509 is about 501.5810075610.

The spelling of 126189509 in words is "one hundred twenty-six million, one hundred eighty-nine thousand, five hundred nine".