21000012100221 has 32 divisors (see below), whose sum is σ = 35091881312256. Its totient is φ = 10851981480000.

The previous prime is 21000012100219. The next prime is 21000012100247. The reversal of 21000012100221 is 12200121000012.

It is not a de Polignac number, because 21000012100221 - 2¹ = 21000012100219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21000012100197 and 21000012100206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000012100621) 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 31 ways as a sum of consecutive naturals, for example, 237937930 + ... + 238026171.

It is an arithmetic number, because the mean of its divisors is an integer number (1096621291008).

Almost surely, 2^{21000012100221} is an apocalyptic number.

21000012100221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21000012100221 is a deficient number, since it is larger than the sum of its proper divisors (14091869212035).

21000012100221 is a wasteful number, since it uses less digits than its factorization.

21000012100221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 475964313.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21000012100221 its reverse (12200121000012), we get a palindrome (33200133100233).

The spelling of 21000012100221 in words is "twenty-one trillion, twelve million, one hundred thousand, two hundred twenty-one".