128278221979 has 2 divisors, whose sum is σ = 128278221980. Its totient is φ = 128278221978.

The previous prime is 128278221949. The next prime is 128278222091. The reversal of 128278221979 is 979122872821.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 128278221979 - 2²¹ = 128276124827 is a prime.

It is not a weakly prime, because it can be changed into another prime (128278221949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64139110989 + 64139110990.

It is an arithmetic number, because the mean of its divisors is an integer number (64139110990).

Almost surely, 2^128278221979 is an apocalyptic number.

128278221979 is a deficient number, since it is larger than the sum of its proper divisors (1).

128278221979 is an equidigital number, since it uses as much as digits as its factorization.

128278221979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4064256, while the sum is 58.

The spelling of 128278221979 in words is "one hundred twenty-eight billion, two hundred seventy-eight million, two hundred twenty-one thousand, nine hundred seventy-nine".