2121212100 has 288 divisors, whose sum is σ = 7233037056. Its totient is φ = 470016000.

The previous prime is 2121212089. The next prime is 2121212101. The reversal of 2121212100 is 12121212.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is not an unprimeable number, because it can be changed into a prime (2121212101) 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, 15483232 + ... + 15483368.

It is an arithmetic number, because the mean of its divisors is an integer number (25114712).

Almost surely, 2^2121212100 is an apocalyptic number.

2121212100 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 2121212100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3616518528).

2121212100 is an abundant number, since it is smaller than the sum of its proper divisors (5111824956).

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

2121212100 is a wasteful number, since it uses less digits than its factorization.

2121212100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 335 (or 328 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 2121212100 is about 46056.6184169007. The cubic root of 2121212100 is about 1284.8764384312.

Adding to 2121212100 its reverse (12121212), we get a palindrome (2133333312).

It can be divided in two parts, 2121 and 212100, that multiplied together give a square (449864100 = 21210²).

The spelling of 2121212100 in words is "two billion, one hundred twenty-one million, two hundred twelve thousand, one hundred".