21121010212221 has 6 divisors (see below), whose sum is σ = 30508125862110. Its totient is φ = 14080673474808.

The previous prime is 21121010212207. The next prime is 21121010212243. The reversal of 21121010212221 is 12221201012112.

21121010212221 is a `hidden beast` number, since 2 + 11 + 210 + 10 + 212 + 221 = 666.

It can be written as a sum of positive squares in only one way, i.e., 20718564615225 + 402445596996 = 4551765^2 + 634386^2 .

It is not a de Polignac number, because 21121010212221 - 2⁹ = 21121010211709 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21121010212194 and 21121010212203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121010212121) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1173389456226 + ... + 1173389456243.

It is an arithmetic number, because the mean of its divisors is an integer number (5084687643685).

Almost surely, 2^{21121010212221} is an apocalyptic number.

It is an amenable number.

21121010212221 is a deficient number, since it is larger than the sum of its proper divisors (9387115649889).

21121010212221 is a wasteful number, since it uses less digits than its factorization.

21121010212221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2346778912475 (or 2346778912472 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21121010212221 its reverse (12221201012112), we get a palindrome (33342211224333).

The spelling of 21121010212221 in words is "twenty-one trillion, one hundred twenty-one billion, ten million, two hundred twelve thousand, two hundred twenty-one".