128421011 has 2 divisors, whose sum is σ = 128421012. Its totient is φ = 128421010.

The previous prime is 128421001. The next prime is 128421023. The reversal of 128421011 is 110124821.

It is a weak prime.

It is an emirp because it is prime and its reverse (110124821) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128421011 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (128421001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64210505 + 64210506.

It is an arithmetic number, because the mean of its divisors is an integer number (64210506).

Almost surely, 2^128421011 is an apocalyptic number.

128421011 is a deficient number, since it is larger than the sum of its proper divisors (1).

128421011 is an equidigital number, since it uses as much as digits as its factorization.

128421011 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 20.

The square root of 128421011 is about 11332.2994577447. The cubic root of 128421011 is about 504.5203575783.

Adding to 128421011 its reverse (110124821), we get a palindrome (238545832).

The spelling of 128421011 in words is "one hundred twenty-eight million, four hundred twenty-one thousand, eleven".