121221100100 has 72 divisors (see below), whose sum is σ = 277895338560. Its totient is φ = 45770382720.

The previous prime is 121221100069. The next prime is 121221100109. The reversal of 121221100100 is 1001122121.

It is not an unprimeable number, because it can be changed into a prime (121221100109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 411137 + ... + 641463.

It is an arithmetic number, because the mean of its divisors is an integer number (3859657480).

Almost surely, 2^121221100100 is an apocalyptic number.

121221100100 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 121221100100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138947669280).

121221100100 is an abundant number, since it is smaller than the sum of its proper divisors (156674238460).

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

121221100100 is a wasteful number, since it uses less digits than its factorization.

121221100100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230637 (or 230630 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 121221100100 its reverse (1001122121), we get a palindrome (122222222221).

The spelling of 121221100100 in words is "one hundred twenty-one billion, two hundred twenty-one million, one hundred thousand, one hundred".