21220120221021 has 12 divisors (see below), whose sum is σ = 30668475636448. Its totient is φ = 14138812565064.

The previous prime is 21220120221011. The next prime is 21220120221023. The reversal of 21220120221021 is 12012202102212.

It is a happy number.

21220120221021 is a `hidden beast` number, since 212 + 20 + 1 + 202 + 210 + 21 = 666.

It is not a de Polignac number, because 21220120221021 - 2¹⁰ = 21220120219997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21220120220985 and 21220120221003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220120221023) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 661170475 + ... + 661202568.

Almost surely, 2^{21220120221021} is an apocalyptic number.

It is an amenable number.

21220120221021 is a deficient number, since it is larger than the sum of its proper divisors (9448355415427).

21220120221021 is a wasteful number, since it uses less digits than its factorization.

21220120221021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1322374832 (or 1322374829 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21220120221021 its reverse (12012202102212), we get a palindrome (33232322323233).

The spelling of 21220120221021 in words is "twenty-one trillion, two hundred twenty billion, one hundred twenty million, two hundred twenty-one thousand, twenty-one".