21121012020221 has 16 divisors (see below), whose sum is σ = 21482305669440. Its totient is φ = 20762770928640.

The previous prime is 21121012020187. The next prime is 21121012020223. The reversal of 21121012020221 is 12202021012112.

It is a cyclic number.

It is not a de Polignac number, because 21121012020221 - 2²² = 21121007825917 is a prime.

It is a super-3 number, since 3×21121012020221³ (a number of 41 digits) contains 333 as substring.

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 21121012020221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121012020223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 393808835 + ... + 393862463.

It is an arithmetic number, because the mean of its divisors is an integer number (1342644104340).

Almost surely, 2^{21121012020221} is an apocalyptic number.

It is an amenable number.

21121012020221 is a deficient number, since it is larger than the sum of its proper divisors (361293649219).

21121012020221 is a wasteful number, since it uses less digits than its factorization.

21121012020221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81964.

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

Adding to 21121012020221 its reverse (12202021012112), we get a palindrome (33323033032333).

The spelling of 21121012020221 in words is "twenty-one trillion, one hundred twenty-one billion, twelve million, twenty thousand, two hundred twenty-one".