21012100210221 has 4 divisors (see below), whose sum is σ = 28016133613632. Its totient is φ = 14008066806812.

The previous prime is 21012100210219. The next prime is 21012100210229. The reversal of 21012100210221 is 12201200121012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21012100210221 - 2¹ = 21012100210219 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21012100210221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012100210229) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3502016701701 + ... + 3502016701706.

It is an arithmetic number, because the mean of its divisors is an integer number (7004033403408).

Almost surely, 2^{21012100210221} is an apocalyptic number.

It is an amenable number.

21012100210221 is a deficient number, since it is larger than the sum of its proper divisors (7004033403411).

21012100210221 is an equidigital number, since it uses as much as digits as its factorization.

21012100210221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7004033403410.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21012100210221 its reverse (12201200121012), we get a palindrome (33213300331233).

The spelling of 21012100210221 in words is "twenty-one trillion, twelve billion, one hundred million, two hundred ten thousand, two hundred twenty-one".