21123100212 has 24 divisors (see below), whose sum is σ = 49297911936. Its totient is φ = 7039507968.

The previous prime is 21123100211. The next prime is 21123100241. The reversal of 21123100212 is 21200132112.

It is a junction number, because it is equal to n+sod(n) for n = 21123100191 and 21123100200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21123100211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 132268 + ... + 244419.

It is an arithmetic number, because the mean of its divisors is an integer number (2054079664).

Almost surely, 2^21123100212 is an apocalyptic number.

It is an amenable number.

21123100212 is an abundant number, since it is smaller than the sum of its proper divisors (28174811724).

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

21123100212 is a wasteful number, since it uses less digits than its factorization.

21123100212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 381367 (or 381365 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 21123100212 its reverse (21200132112), we get a palindrome (42323232324).

The spelling of 21123100212 in words is "twenty-one billion, one hundred twenty-three million, one hundred thousand, two hundred twelve".