128422436721 has 16 divisors (see below), whose sum is σ = 172019295360. Its totient is φ = 85221152640.

The previous prime is 128422436717. The next prime is 128422436741. The reversal of 128422436721 is 127634224821.

It is a happy number.

It is not a de Polignac number, because 128422436721 - 2² = 128422436717 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (128422436741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 472860 + ... + 693138.

It is an arithmetic number, because the mean of its divisors is an integer number (10751205960).

Almost surely, 2^128422436721 is an apocalyptic number.

It is an amenable number.

128422436721 is a deficient number, since it is larger than the sum of its proper divisors (43596858639).

128422436721 is a wasteful number, since it uses less digits than its factorization.

128422436721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221176.

The product of its digits is 258048, while the sum is 42.

The spelling of 128422436721 in words is "one hundred twenty-eight billion, four hundred twenty-two million, four hundred thirty-six thousand, seven hundred twenty-one".