1011111121221 has 16 divisors (see below), whose sum is σ = 1366658711040. Its totient is φ = 664819384320.

The previous prime is 1011111121187. The next prime is 1011111121253. The reversal of 1011111121221 is 1221211111101.

It is not a de Polignac number, because 1011111121221 - 2¹⁴ = 1011111104837 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1011111121221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1011111121621) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10400325 + ... + 10497093.

It is an arithmetic number, because the mean of its divisors is an integer number (85416169440).

Almost surely, 2^{1011111121221} is an apocalyptic number.

It is an amenable number.

1011111121221 is a deficient number, since it is larger than the sum of its proper divisors (355547589819).

1011111121221 is an equidigital number, since it uses as much as digits as its factorization.

1011111121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144556.

The product of its (nonzero) digits is 8, while the sum is 15.

Adding to 1011111121221 its reverse (1221211111101), we get a palindrome (2232322232322).

The spelling of 1011111121221 in words is "one trillion, eleven billion, one hundred eleven million, one hundred twenty-one thousand, two hundred twenty-one".