2101212100 has 72 divisors (see below), whose sum is σ = 4991057288. Its totient is φ = 763084800.

The previous prime is 2101212049. The next prime is 2101212103. The reversal of 2101212100 is 12121012.

It can be written as a sum of positive squares in 12 ways, for example, as 1054430784 + 1046781316 = 32472^2 + 32354^2 .

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 (2101212103) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 66052 + ... + 92548.

Almost surely, 2^2101212100 is an apocalyptic number.

2101212100 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 2101212100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2495528644).

2101212100 is an abundant number, since it is smaller than the sum of its proper divisors (2889845188).

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

2101212100 is a wasteful number, since it uses less digits than its factorization.

2101212100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26585 (or 26578 counting only the distinct ones).

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

The square root of 2101212100 is about 45838.9801369969. The cubic root of 2101212100 is about 1280.8254969661.

Adding to 2101212100 its reverse (12121012), we get a palindrome (2113333112).

The spelling of 2101212100 in words is "two billion, one hundred one million, two hundred twelve thousand, one hundred".