21120212100221 has 8 divisors (see below), whose sum is σ = 22745395995000. Its totient is φ = 19495107090432.

The previous prime is 21120212100217. The next prime is 21120212100263. The reversal of 21120212100221 is 12200121202112.

It can be written as a sum of positive squares in 4 ways, for example, as 1259195935321 + 19861016164900 = 1122139^2 + 4456570^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21120212100221 - 2² = 21120212100217 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21120212100221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120212100121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19164596 + ... + 20236653.

It is an arithmetic number, because the mean of its divisors is an integer number (2843174499375).

Almost surely, 2^{21120212100221} is an apocalyptic number.

It is an amenable number.

21120212100221 is a deficient number, since it is larger than the sum of its proper divisors (1625183894779).

21120212100221 is a wasteful number, since it uses less digits than its factorization.

21120212100221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39442495.

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

Adding to 21120212100221 its reverse (12200121202112), we get a palindrome (33320333302333).

The spelling of 21120212100221 in words is "twenty-one trillion, one hundred twenty billion, two hundred twelve million, one hundred thousand, two hundred twenty-one".