128433731721 has 8 divisors (see below), whose sum is σ = 174476013120. Its totient is φ = 84006969072.

The previous prime is 128433731711. The next prime is 128433731731. The reversal of 128433731721 is 127137334821.

It is an interprime number because it is at equal distance from previous prime (128433731711) and next prime (128433731731).

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

It is not a de Polignac number, because 128433731721 - 2¹⁹ = 128433207433 is a prime.

It is not an unprimeable number, because it can be changed into a prime (128433731711) 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, 403879501 + ... + 403879818.

It is an arithmetic number, because the mean of its divisors is an integer number (21809501640).

Almost surely, 2^128433731721 is an apocalyptic number.

It is an amenable number.

128433731721 is a deficient number, since it is larger than the sum of its proper divisors (46042281399).

128433731721 is an equidigital number, since it uses as much as digits as its factorization.

128433731721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 807759375.

The product of its digits is 169344, while the sum is 42.

The spelling of 128433731721 in words is "one hundred twenty-eight billion, four hundred thirty-three million, seven hundred thirty-one thousand, seven hundred twenty-one".