121800 has 96 divisors (see below), whose sum is σ = 446400. Its totient is φ = 26880.

The previous prime is 121789. The next prime is 121843. The reversal of 121800 is 8121.

121800 = T₁₆₀ + T₁₆₁ + ... + T₁₆₈.

It is a happy number.

It is a Cunningham number, because it is equal to 349²-1.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4186 + ... + 4214.

It is an arithmetic number, because the mean of its divisors is an integer number (4650).

2¹²¹⁸⁰⁰ is an apocalyptic number.

121800 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 121800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (223200).

121800 is an abundant number, since it is smaller than the sum of its proper divisors (324600).

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

121800 is a wasteful number, since it uses less digits than its factorization.

121800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55 (or 46 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 121800 is about 348.9985673323. The cubic root of 121800 is about 49.5696397622.

Adding to 121800 its reverse (8121), we get a palindrome (129921).

The spelling of 121800 in words is "one hundred twenty-one thousand, eight hundred".