21121212202100 has 18 divisors (see below), whose sum is σ = 45833030478774. Its totient is φ = 8448484880800.

The previous prime is 21121212202007. The next prime is 21121212202121. The reversal of 21121212202100 is 120221212112.

It can be written as a sum of positive squares in 3 ways, for example, as 6782840164 + 21114429361936 = 82358^2 + 4595044^2 .

It is a super-2 number, since 2×21121212202100² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 105606060911 + ... + 105606061110.

It is an arithmetic number, because the mean of its divisors is an integer number (2546279471043).

Almost surely, 2^{21121212202100} is an apocalyptic number.

21121212202100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121212202100 is an abundant number, since it is smaller than the sum of its proper divisors (24711818276674).

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

21121212202100 is a wasteful number, since it uses less digits than its factorization.

21121212202100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211212122035 (or 211212122028 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21121212202100 its reverse (120221212112), we get a palindrome (21241433414212).

The spelling of 21121212202100 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twelve million, two hundred two thousand, one hundred".