126640121 has 2 divisors, whose sum is σ = 126640122. Its totient is φ = 126640120.

The previous prime is 126640109. The next prime is 126640141. The reversal of 126640121 is 121046621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 126450025 + 190096 = 11245^2 + 436^2 .

It is a cyclic number.

It is not a de Polignac number, because 126640121 - 2¹⁴ = 126623737 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (126640141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 63320060 + 63320061.

It is an arithmetic number, because the mean of its divisors is an integer number (63320061).

Almost surely, 2^126640121 is an apocalyptic number.

It is an amenable number.

126640121 is a deficient number, since it is larger than the sum of its proper divisors (1).

126640121 is an equidigital number, since it uses as much as digits as its factorization.

126640121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 126640121 is about 11253.4492934389. The cubic root of 126640121 is about 502.1773326818.

Adding to 126640121 its reverse (121046621), we get a palindrome (247686742).

The spelling of 126640121 in words is "one hundred twenty-six million, six hundred forty thousand, one hundred twenty-one".