1001021111221 has 2 divisors, whose sum is σ = 1001021111222. Its totient is φ = 1001021111220.

The previous prime is 1001021111219. The next prime is 1001021111227. The reversal of 1001021111221 is 1221111201001.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 912149154225 + 88871956996 = 955065^2 + 298114^2 .

It is a cyclic number.

It is not a de Polignac number, because 1001021111221 - 2¹ = 1001021111219 is a prime.

It is a super-2 number, since 2×1001021111221² (a number of 25 digits) contains 22 as substring.

Together with 1001021111219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1001021111227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500510555610 + 500510555611.

It is an arithmetic number, because the mean of its divisors is an integer number (500510555611).

Almost surely, 2^{1001021111221} is an apocalyptic number.

It is an amenable number.

1001021111221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1001021111221 is an equidigital number, since it uses as much as digits as its factorization.

1001021111221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 1001021111221 its reverse (1221111201001), we get a palindrome (2222132312222).

The spelling of 1001021111221 in words is "one trillion, one billion, twenty-one million, one hundred eleven thousand, two hundred twenty-one".