128029121 has 4 divisors (see below), whose sum is σ = 139668144. Its totient is φ = 116390100.

The previous prime is 128029067. The next prime is 128029129. The reversal of 128029121 is 121920821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128029121 is a prime.

It is not an unprimeable number, because it can be changed into a prime (128029129) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5819495 + ... + 5819516.

It is an arithmetic number, because the mean of its divisors is an integer number (34917036).

Almost surely, 2^128029121 is an apocalyptic number.

128029121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

128029121 is a deficient number, since it is larger than the sum of its proper divisors (11639023).

128029121 is a wasteful number, since it uses less digits than its factorization.

128029121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11639022.

The product of its (nonzero) digits is 576, while the sum is 26.

The square root of 128029121 is about 11314.9954043296. The cubic root of 128029121 is about 504.0066359775.

Adding to 128029121 its reverse (121920821), we get a palindrome (249949942).

The spelling of 128029121 in words is "one hundred twenty-eight million, twenty-nine thousand, one hundred twenty-one".