121221900 has 288 divisors, whose sum is σ = 437472000. Its totient is φ = 28615680.

The previous prime is 121221889. The next prime is 121221901. The reversal of 121221900 is 9122121.

It is a super-2 number, since 2×121221900² = 29389498079220000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (121221901) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 872031 + ... + 872169.

It is an arithmetic number, because the mean of its divisors is an integer number (1519000).

Almost surely, 2^121221900 is an apocalyptic number.

121221900 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 121221900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (218736000).

121221900 is an abundant number, since it is smaller than the sum of its proper divisors (316250100).

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

121221900 is a wasteful number, since it uses less digits than its factorization.

121221900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198 (or 185 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 121221900 is about 11010.0817435658. The cubic root of 121221900 is about 494.9109114235.

The spelling of 121221900 in words is "one hundred twenty-one million, two hundred twenty-one thousand, nine hundred".