1021012221221 has 4 divisors (see below), whose sum is σ = 1021736858700. Its totient is φ = 1020287583744.

The previous prime is 1021012221197. The next prime is 1021012221227. The reversal of 1021012221221 is 1221222101201.

1021012221221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 525059652100 + 495952569121 = 724610^2 + 704239^2 .

It is a cyclic number.

It is not a de Polignac number, because 1021012221221 - 2¹⁰ = 1021012220197 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1021012221221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021012221227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 362316626 + ... + 362319443.

It is an arithmetic number, because the mean of its divisors is an integer number (255434214675).

Almost surely, 2^{1021012221221} is an apocalyptic number.

It is an amenable number.

1021012221221 is a deficient number, since it is larger than the sum of its proper divisors (724637479).

1021012221221 is an equidigital number, since it uses as much as digits as its factorization.

1021012221221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 724637478.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 1021012221221 its reverse (1221222101201), we get a palindrome (2242234322422).

The spelling of 1021012221221 in words is "one trillion, twenty-one billion, twelve million, two hundred twenty-one thousand, two hundred twenty-one".