2121021121100 has 144 divisors (see below), whose sum is σ = 5621607194112. Its totient is φ = 678033392640.

The previous prime is 2121021121097. The next prime is 2121021121103. The reversal of 2121021121100 is 11211201212.

It is an interprime number because it is at equal distance from previous prime (2121021121097) and next prime (2121021121103).

It is a Harshad number since it is a multiple of its sum of digits (14).

It is not an unprimeable number, because it can be changed into a prime (2121021121103) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 440417 + ... + 2106183.

It is an arithmetic number, because the mean of its divisors is an integer number (39038938848).

Almost surely, 2^{2121021121100} is an apocalyptic number.

2121021121100 is a gapful number since it is divisible by the number (20) 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 2121021121100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2810803597056).

2121021121100 is an abundant number, since it is smaller than the sum of its proper divisors (3500586073012).

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

2121021121100 is a wasteful number, since it uses less digits than its factorization.

2121021121100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1665912 (or 1665905 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 2121021121100 its reverse (11211201212), we get a palindrome (2132232322312).

The spelling of 2121021121100 in words is "two trillion, one hundred twenty-one billion, twenty-one million, one hundred twenty-one thousand, one hundred".