128633425450021 has 2 divisors, whose sum is σ = 128633425450022. Its totient is φ = 128633425450020.

The previous prime is 128633425449967. The next prime is 128633425450067. The reversal of 128633425450021 is 120054524336821.

It is an a-pointer prime, because the next prime (128633425450067) can be obtained adding 128633425450021 to its sum of digits (46).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 122063585001121 + 6569840448900 = 11048239^2 + 2563170^2 .

It is an emirp because it is prime and its reverse (120054524336821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 128633425450021 - 2⁹ = 128633425449509 is a prime.

It is a super-2 number, since 2×128633425450021² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128633425451021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64316712725010 + 64316712725011.

It is an arithmetic number, because the mean of its divisors is an integer number (64316712725011).

Almost surely, 2^{128633425450021} is an apocalyptic number.

It is an amenable number.

128633425450021 is a deficient number, since it is larger than the sum of its proper divisors (1).

128633425450021 is an equidigital number, since it uses as much as digits as its factorization.

128633425450021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1382400, while the sum is 46.

Adding to 128633425450021 its reverse (120054524336821), we get a palindrome (248687949786842).

The spelling of 128633425450021 in words is "one hundred twenty-eight trillion, six hundred thirty-three billion, four hundred twenty-five million, four hundred fifty thousand, twenty-one".