121989924 has 72 divisors (see below), whose sum is σ = 361041408. Its totient is φ = 34001280.

The previous prime is 121989913. The next prime is 121989961. The reversal of 121989924 is 429989121.

It is a self number, because there is not a number n which added to its sum of digits gives 121989924.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4429 + ... + 16235.

It is an arithmetic number, because the mean of its divisors is an integer number (5014464).

Almost surely, 2^121989924 is an apocalyptic number.

121989924 is a gapful number since it is divisible by the number (14) 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 121989924, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (180520704).

121989924 is an abundant number, since it is smaller than the sum of its proper divisors (239051484).

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

121989924 is a wasteful number, since it uses less digits than its factorization.

121989924 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11865 (or 11860 counting only the distinct ones).

The product of its digits is 93312, while the sum is 45.

The square root of 121989924 is about 11044.9048886806. The cubic root of 121989924 is about 495.9539119941.

It can be divided in two parts, 12198 and 9924, that added together give a palindrome (22122).

The spelling of 121989924 in words is "one hundred twenty-one million, nine hundred eighty-nine thousand, nine hundred twenty-four".