121709928 has 64 divisors (see below), whose sum is σ = 321638400. Its totient is φ = 38301120.

The previous prime is 121709923. The next prime is 121709933. The reversal of 121709928 is 829907121.

It is an interprime number because it is at equal distance from previous prime (121709923) and next prime (121709933).

It is not an unprimeable number, because it can be changed into a prime (121709921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42213 + ... + 45003.

It is an arithmetic number, because the mean of its divisors is an integer number (5025600).

Almost surely, 2^121709928 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 121709928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (160819200).

121709928 is an abundant number, since it is smaller than the sum of its proper divisors (199928472).

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

121709928 is a wasteful number, since it uses less digits than its factorization.

121709928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2902 (or 2898 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 39.

The square root of 121709928 is about 11032.2222602701. Note that the first 4 decimals coincide. The cubic root of 121709928 is about 495.5741771069.

The spelling of 121709928 in words is "one hundred twenty-one million, seven hundred nine thousand, nine hundred twenty-eight".