126978809 has 2 divisors, whose sum is σ = 126978810. Its totient is φ = 126978808.

The previous prime is 126978781. The next prime is 126978827. The reversal of 126978809 is 908879621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 97515625 + 29463184 = 9875^2 + 5428^2 .

It is a cyclic number.

It is not a de Polignac number, because 126978809 - 2²⁴ = 110201593 is a prime.

It is a super-2 number, since 2×126978809² = 32247235870116962, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (126978889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 63489404 + 63489405.

It is an arithmetic number, because the mean of its divisors is an integer number (63489405).

Almost surely, 2^126978809 is an apocalyptic number.

It is an amenable number.

126978809 is a deficient number, since it is larger than the sum of its proper divisors (1).

126978809 is an equidigital number, since it uses as much as digits as its factorization.

126978809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 435456, while the sum is 50.

The square root of 126978809 is about 11268.4874317718. The cubic root of 126978809 is about 502.6246107306.

The spelling of 126978809 in words is "one hundred twenty-six million, nine hundred seventy-eight thousand, eight hundred nine".