128409421921 has 8 divisors (see below), whose sum is σ = 142001951904. Its totient is φ = 115136716320.

The previous prime is 128409421909. The next prime is 128409421957. The reversal of 128409421921 is 129124904821.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 128409421921 - 2⁷ = 128409421793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128409421901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 79955251 + ... + 79956856.

It is an arithmetic number, because the mean of its divisors is an integer number (17750243988).

Almost surely, 2^128409421921 is an apocalyptic number.

128409421921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

128409421921 is a deficient number, since it is larger than the sum of its proper divisors (13592529983).

128409421921 is a wasteful number, since it uses less digits than its factorization.

128409421921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159912191.

The product of its (nonzero) digits is 82944, while the sum is 43.

The spelling of 128409421921 in words is "one hundred twenty-eight billion, four hundred nine million, four hundred twenty-one thousand, nine hundred twenty-one".