128213721289 has 2 divisors, whose sum is σ = 128213721290. Its totient is φ = 128213721288.

The previous prime is 128213721271. The next prime is 128213721401. The reversal of 128213721289 is 982127312821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 127992217600 + 221503689 = 357760^2 + 14883^2 .

It is a cyclic number.

It is not a de Polignac number, because 128213721289 - 2⁷ = 128213721161 is a prime.

It is not a weakly prime, because it can be changed into another prime (128213721589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64106860644 + 64106860645.

It is an arithmetic number, because the mean of its divisors is an integer number (64106860645).

Almost surely, 2^128213721289 is an apocalyptic number.

It is an amenable number.

128213721289 is a deficient number, since it is larger than the sum of its proper divisors (1).

128213721289 is an equidigital number, since it uses as much as digits as its factorization.

128213721289 is an evil number, because the sum of its binary digits is even.

The product of its digits is 193536, while the sum is 46.

The spelling of 128213721289 in words is "one hundred twenty-eight billion, two hundred thirteen million, seven hundred twenty-one thousand, two hundred eighty-nine".