1021111011221 has 24 divisors (see below), whose sum is σ = 1195029621720. Its totient is φ = 869940836352.

The previous prime is 1021111011199. The next prime is 1021111011253. The reversal of 1021111011221 is 1221101111201.

It can be written as a sum of positive squares in 4 ways, for example, as 761404582225 + 259706428996 = 872585^2 + 509614^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1021111011221 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1021111011196 and 1021111011205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021111011521) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6577325 + ... + 6730781.

It is an arithmetic number, because the mean of its divisors is an integer number (49792900905).

Almost surely, 2^{1021111011221} is an apocalyptic number.

It is an amenable number.

1021111011221 is a deficient number, since it is larger than the sum of its proper divisors (173918610499).

1021111011221 is a wasteful number, since it uses less digits than its factorization.

1021111011221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154293 (or 154286 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 14.

Adding to 1021111011221 its reverse (1221101111201), we get a palindrome (2242212122422).

The spelling of 1021111011221 in words is "one trillion, twenty-one billion, one hundred eleven million, eleven thousand, two hundred twenty-one".