1021112221221 has 12 divisors (see below), whose sum is σ = 1525799871180. Its totient is φ = 657267636480.

The previous prime is 1021112221189. The next prime is 1021112221223. The reversal of 1021112221221 is 1221222111201.

1021112221221 is a `hidden beast` number, since 1 + 0 + 211 + 12 + 221 + 221 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 872802509121 + 148309712100 = 934239^2 + 385110^2 .

It is not a de Polignac number, because 1021112221221 - 2⁵ = 1021112221189 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1021112221194 and 1021112221203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021112221223) 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, 1956153420 + ... + 1956153941.

It is an arithmetic number, because the mean of its divisors is an integer number (127149989265).

Almost surely, 2^{1021112221221} is an apocalyptic number.

It is an amenable number.

1021112221221 is a deficient number, since it is larger than the sum of its proper divisors (504687649959).

1021112221221 is a wasteful number, since it uses less digits than its factorization.

1021112221221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3912307396 (or 3912307393 counting only the distinct ones).

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

Adding to 1021112221221 its reverse (1221222111201), we get a palindrome (2242334332422).

The spelling of 1021112221221 in words is "one trillion, twenty-one billion, one hundred twelve million, two hundred twenty-one thousand, two hundred twenty-one".