2121100010100 has 216 divisors, whose sum is σ = 6867646301880. Its totient is φ = 547156823040.

The previous prime is 2121100010083. The next prime is 2121100010119. The reversal of 2121100010100 is 10100011212.

It is a happy number.

It can be written as a sum of positive squares in 12 ways, for example, as 62558013456 + 2058541996644 = 250116^2 + 1434762^2 .

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 5576806 + ... + 5944994.

It is an arithmetic number, because the mean of its divisors is an integer number (31794658805).

Almost surely, 2^{2121100010100} is an apocalyptic number.

2121100010100 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 2121100010100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3433823150940).

2121100010100 is an abundant number, since it is smaller than the sum of its proper divisors (4746546291780).

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

2121100010100 is a wasteful number, since it uses less digits than its factorization.

2121100010100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 368419 (or 368409 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 2121100010100 its reverse (10100011212), we get a palindrome (2131200021312).

The spelling of 2121100010100 in words is "two trillion, one hundred twenty-one billion, one hundred million, ten thousand, one hundred".