1221221000221 has 16 divisors (see below), whose sum is σ = 1279558828800. Its totient is φ = 1163324181888.

The previous prime is 1221221000213. The next prime is 1221221000227. The reversal of 1221221000221 is 1220001221221.

It is a happy number.

It is not a de Polignac number, because 1221221000221 - 2³ = 1221221000213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221221000195 and 1221221000204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221221000227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12943465 + ... + 13037473.

It is an arithmetic number, because the mean of its divisors is an integer number (79972426800).

Almost surely, 2^{1221221000221} is an apocalyptic number.

It is an amenable number.

1221221000221 is a deficient number, since it is larger than the sum of its proper divisors (58337828579).

1221221000221 is a wasteful number, since it uses less digits than its factorization.

1221221000221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96348.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 1221221000221 its reverse (1220001221221), we get a palindrome (2441222221442).

It can be divided in two parts, 1221221000 and 221, that added together give a palindrome (1221221221).

The spelling of 1221221000221 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-one million, two hundred twenty-one", and thus it is an aban number.