1221011100221 has 8 divisors (see below), whose sum is σ = 1332224864064. Its totient is φ = 1109832795520.

The previous prime is 1221011100139. The next prime is 1221011100227. The reversal of 1221011100221 is 1220011101221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221011100221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221011100196 and 1221011100205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221011100227) 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, 8792756 + ... + 8930541.

It is an arithmetic number, because the mean of its divisors is an integer number (166528108008).

Almost surely, 2^{1221011100221} is an apocalyptic number.

1221011100221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221011100221 is a deficient number, since it is larger than the sum of its proper divisors (111213763843).

1221011100221 is a wasteful number, since it uses less digits than its factorization.

1221011100221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17729571.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 1221011100221 its reverse (1220011101221), we get a palindrome (2441022201442).

The spelling of 1221011100221 in words is "one trillion, two hundred twenty-one billion, eleven million, one hundred thousand, two hundred twenty-one".