21021222111221 has 8 divisors (see below), whose sum is σ = 21079057490304. Its totient is φ = 20963389759200.

The previous prime is 21021222111203. The next prime is 21021222111259. The reversal of 21021222111221 is 12211122212012.

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 21021222111221 - 2⁴² = 16623175600117 is a prime.

It is a super-2 number, since 2×21021222111221² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21021222111193 and 21021222111202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021222111121) 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, 13521161 + ... + 14995473.

It is an arithmetic number, because the mean of its divisors is an integer number (2634882186288).

Almost surely, 2^{21021222111221} is an apocalyptic number.

It is an amenable number.

21021222111221 is a deficient number, since it is larger than the sum of its proper divisors (57835379083).

21021222111221 is a wasteful number, since it uses less digits than its factorization.

21021222111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1513531.

The product of its (nonzero) digits is 128, while the sum is 20.

Adding to 21021222111221 its reverse (12211122212012), we get a palindrome (33232344323233).

The spelling of 21021222111221 in words is "twenty-one trillion, twenty-one billion, two hundred twenty-two million, one hundred eleven thousand, two hundred twenty-one".