121305128 has 64 divisors (see below), whose sum is σ = 276514560. Its totient is φ = 48761856.

The previous prime is 121305127. The next prime is 121305157. The reversal of 121305128 is 821503121.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is not an unprimeable number, because it can be changed into a prime (121305127) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 67376 + ... + 69152.

It is an arithmetic number, because the mean of its divisors is an integer number (4320540).

Almost surely, 2^121305128 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121305128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138257280).

121305128 is an abundant number, since it is smaller than the sum of its proper divisors (155209432).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

121305128 is a wasteful number, since it uses less digits than its factorization.

121305128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1866 (or 1862 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 23.

The square root of 121305128 is about 11013.8607218359. The cubic root of 121305128 is about 495.0241500988.

Adding to 121305128 its reverse (821503121), we get a palindrome (942808249).

The spelling of 121305128 in words is "one hundred twenty-one million, three hundred five thousand, one hundred twenty-eight".