21010122120221 has 8 divisors (see below), whose sum is σ = 22630838918520. Its totient is φ = 19390055830272.

The previous prime is 21010122120217. The next prime is 21010122120287. The reversal of 21010122120221 is 12202122101012.

It can be written as a sum of positive squares in 4 ways, for example, as 315001562500 + 20695120557721 = 561250^2 + 4549189^2 .

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 21010122120221 - 2² = 21010122120217 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 21010122120221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010122120521) 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, 162560000 + ... + 162689193.

It is an arithmetic number, because the mean of its divisors is an integer number (2828854864815).

Almost surely, 2^{21010122120221} is an apocalyptic number.

It is an amenable number.

21010122120221 is a deficient number, since it is larger than the sum of its proper divisors (1620716798299).

21010122120221 is a wasteful number, since it uses less digits than its factorization.

21010122120221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325254175.

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

Adding to 21010122120221 its reverse (12202122101012), we get a palindrome (33212244221233).

The spelling of 21010122120221 in words is "twenty-one trillion, ten billion, one hundred twenty-two million, one hundred twenty thousand, two hundred twenty-one".