1221402100221 has 8 divisors (see below), whose sum is σ = 1809484592960. Its totient is φ = 814268066796.

The previous prime is 1221402100211. The next prime is 1221402100223. The reversal of 1221402100221 is 1220012041221.

1221402100221 is a `hidden beast` number, since 12 + 21 + 402 + 10 + 0 + 221 = 666.

It is not a de Polignac number, because 1221402100221 - 2²⁷ = 1221267882493 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221402100194 and 1221402100203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221402100223) 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, 22618557385 + ... + 22618557438.

It is an arithmetic number, because the mean of its divisors is an integer number (226185574120).

Almost surely, 2^{1221402100221} is an apocalyptic number.

It is an amenable number.

1221402100221 is a deficient number, since it is larger than the sum of its proper divisors (588082492739).

1221402100221 is an equidigital number, since it uses as much as digits as its factorization.

1221402100221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45237114832 (or 45237114826 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 1221402100221 its reverse (1220012041221), we get a palindrome (2441414141442).

The spelling of 1221402100221 in words is "one trillion, two hundred twenty-one billion, four hundred two million, one hundred thousand, two hundred twenty-one".