121980 has 48 divisors (see below), whose sum is σ = 362880. Its totient is φ = 30528.

The previous prime is 121967. The next prime is 121993. The reversal of 121980 is 89121.

It is an interprime number because it is at equal distance from previous prime (121967) and next prime (121993).

It is an Ulam number.

It is a congruent number.

It is an unprimeable number.

121980 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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, 1087 + ... + 1193.

It is an arithmetic number, because the mean of its divisors is an integer number (7560).

2¹²¹⁹⁸⁰ is an apocalyptic number.

121980 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 121980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (181440).

121980 is an abundant number, since it is smaller than the sum of its proper divisors (240900).

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

121980 is a wasteful number, since it uses less digits than its factorization.

121980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138 (or 136 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 21.

The square root of 121980 is about 349.2563528413. The cubic root of 121980 is about 49.5940462850.

The spelling of 121980 in words is "one hundred twenty-one thousand, nine hundred eighty".