121989120 has 288 divisors, whose sum is σ = 449336160. Its totient is φ = 28016640.

The previous prime is 121989107. The next prime is 121989121. The reversal of 121989120 is 21989121.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121989121) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6420471 + ... + 6420489.

It is an arithmetic number, because the mean of its divisors is an integer number (1560195).

Almost surely, 2^121989120 is an apocalyptic number.

121989120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121989120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (224668080).

121989120 is an abundant number, since it is smaller than the sum of its proper divisors (327347040).

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

121989120 is a wasteful number, since it uses less digits than its factorization.

121989120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79 (or 40 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 33.

The square root of 121989120 is about 11044.8684917476. The cubic root of 121989120 is about 495.9528224292.

Subtracting from 121989120 its reverse (21989121), we obtain a palindrome (99999999).

The spelling of 121989120 in words is "one hundred twenty-one million, nine hundred eighty-nine thousand, one hundred twenty".