1021211121221 has 8 divisors (see below), whose sum is σ = 1030608985560. Its totient is φ = 1011813783552.

The previous prime is 1021211121209. The next prime is 1021211121251. The reversal of 1021211121221 is 1221211121201.

It can be written as a sum of positive squares in 4 ways, for example, as 537127752100 + 484083369121 = 732890^2 + 695761^2 .

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 1021211121221 - 2¹⁸ = 1021210859077 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 1021211121221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021211121251) 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, 4514801 + ... + 4735593.

It is an arithmetic number, because the mean of its divisors is an integer number (128826123195).

Almost surely, 2^{1021211121221} is an apocalyptic number.

It is an amenable number.

1021211121221 is a deficient number, since it is larger than the sum of its proper divisors (9397864339).

1021211121221 is a wasteful number, since it uses less digits than its factorization.

1021211121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263335.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 1021211121221 its reverse (1221211121201), we get a palindrome (2242422242422).

The spelling of 1021211121221 in words is "one trillion, twenty-one billion, two hundred eleven million, one hundred twenty-one thousand, two hundred twenty-one".