121551021200 has 120 divisors (see below), whose sum is σ = 339401520960. Its totient is φ = 40968230400.

The previous prime is 121551021197. The next prime is 121551021209. The reversal of 121551021200 is 2120155121.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (121551021209) by changing a digit.

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, 202691 + ... + 533090.

It is an arithmetic number, because the mean of its divisors is an integer number (2828346008).

Almost surely, 2^121551021200 is an apocalyptic number.

121551021200 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121551021200 is an abundant number, since it is smaller than the sum of its proper divisors (217850499760).

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

121551021200 is a wasteful number, since it uses less digits than its factorization.

121551021200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 735865 (or 735854 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 20.

Adding to 121551021200 its reverse (2120155121), we get a palindrome (123671176321).

The spelling of 121551021200 in words is "one hundred twenty-one billion, five hundred fifty-one million, twenty-one thousand, two hundred".