21112212122100 has 720 divisors, whose sum is σ = 75107651927616. Its totient is φ = 5087453184000.

The previous prime is 21112212122077. The next prime is 21112212122179. The reversal of 21112212122100 is 122121221112.

21112212122100 is a `hidden beast` number, since 21 + 1 + 1 + 221 + 212 + 210 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 18799832139 + ... + 18799833261.

Almost surely, 2^{21112212122100} is an apocalyptic number.

21112212122100 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 21112212122100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37553825963808).

21112212122100 is an abundant number, since it is smaller than the sum of its proper divisors (53995439805516).

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

21112212122100 is a wasteful number, since it uses less digits than its factorization.

21112212122100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2238 (or 2222 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21112212122100 its reverse (122121221112), we get a palindrome (21234333343212).

The spelling of 21112212122100 in words is "twenty-one trillion, one hundred twelve billion, two hundred twelve million, one hundred twenty-two thousand, one hundred".