21020220221 has 64 divisors (see below), whose sum is σ = 28896860160. Its totient is φ = 14761992960.

The previous prime is 21020220217. The next prime is 21020220281. The reversal of 21020220221 is 12202202012.

It is not a de Polignac number, because 21020220221 - 2² = 21020220217 is a prime.

It is a super-3 number, since 3×21020220221³ (a number of 32 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21020220196 and 21020220205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020220211) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 9271130 + ... + 9273396.

It is an arithmetic number, because the mean of its divisors is an integer number (451513440).

Almost surely, 2^21020220221 is an apocalyptic number.

It is an amenable number.

21020220221 is a deficient number, since it is larger than the sum of its proper divisors (7876639939).

21020220221 is a wasteful number, since it uses less digits than its factorization.

21020220221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2514.

The product of its (nonzero) digits is 64, while the sum is 14.

Adding to 21020220221 its reverse (12202202012), we get a palindrome (33222422233).

The spelling of 21020220221 in words is "twenty-one billion, twenty million, two hundred twenty thousand, two hundred twenty-one".