121221100 has 216 divisors, whose sum is σ = 361570608. Its totient is φ = 34675200.

The previous prime is 121221077. The next prime is 121221103. The reversal of 121221100 is 1122121.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (121221103) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 700614 + ... + 700786.

It is an arithmetic number, because the mean of its divisors is an integer number (1673938).

Almost surely, 2^121221100 is an apocalyptic number.

121221100 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 121221100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (180785304).

121221100 is an abundant number, since it is smaller than the sum of its proper divisors (240349508).

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

121221100 is a wasteful number, since it uses less digits than its factorization.

121221100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 225 (or 211 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 121221100 is about 11010.0454131670. The cubic root of 121221100 is about 494.9098227049.

Adding to 121221100 its reverse (1122121), we get a palindrome (122343221).

The spelling of 121221100 in words is "one hundred twenty-one million, two hundred twenty-one thousand, one hundred".