1221102111021 has 16 divisors (see below), whose sum is σ = 1845660411840. Its totient is φ = 711897586560.

The previous prime is 1221102111017. The next prime is 1221102111023. The reversal of 1221102111021 is 1201112011221.

It is a happy number.

It is not a de Polignac number, because 1221102111021 - 2² = 1221102111017 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221102111023) 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, 823954800 + ... + 823956281.

It is an arithmetic number, because the mean of its divisors is an integer number (115353775740).

Almost surely, 2^{1221102111021} is an apocalyptic number.

It is an amenable number.

1221102111021 is a deficient number, since it is larger than the sum of its proper divisors (624558300819).

1221102111021 is a wasteful number, since it uses less digits than its factorization.

1221102111021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1647911116.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 1221102111021 its reverse (1201112011221), we get a palindrome (2422214122242).

The spelling of 1221102111021 in words is "one trillion, two hundred twenty-one billion, one hundred two million, one hundred eleven thousand, twenty-one".