212100220000021 has 16 divisors (see below), whose sum is σ = 225003658239360. Its totient is φ = 199244532695040.

The previous prime is 212100219999923. The next prime is 212100220000049. The reversal of 212100220000021 is 120000022001212.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-212100220000021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 212100219999956 and 212100220000010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212100220000051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16926376 + ... + 26659006.

It is an arithmetic number, because the mean of its divisors is an integer number (14062728639960).

Almost surely, 2^{212100220000021} is an apocalyptic number.

It is an amenable number.

212100220000021 is a deficient number, since it is larger than the sum of its proper divisors (12903438239339).

212100220000021 is a wasteful number, since it uses less digits than its factorization.

212100220000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9735084.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 212100220000021 its reverse (120000022001212), we get a palindrome (332100242001233).

The spelling of 212100220000021 in words is "two hundred twelve trillion, one hundred billion, two hundred twenty million, twenty-one", and thus it is an aban number.