121721200 has 30 divisors (see below), whose sum is σ = 292436144. Its totient is φ = 48688320.

The previous prime is 121721191. The next prime is 121721203. The reversal of 121721200 is 2127121.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121721203) 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 5 ways as a sum of consecutive naturals, for example, 151752 + ... + 152551.

Almost surely, 2^121721200 is an apocalyptic number.

121721200 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121721200 is an abundant number, since it is smaller than the sum of its proper divisors (170714944).

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

121721200 is a wasteful number, since it uses less digits than its factorization.

121721200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304321 (or 304310 counting only the distinct ones).

The product of its (nonzero) digits is 56, while the sum is 16.

The square root of 121721200 is about 11032.7331155974. The cubic root of 121721200 is about 495.5894756115.

Adding to 121721200 its reverse (2127121), we get a palindrome (123848321).

The spelling of 121721200 in words is "one hundred twenty-one million, seven hundred twenty-one thousand, two hundred".