1221222021021 has 8 divisors (see below), whose sum is σ = 1809217808960. Its totient is φ = 814148013996.

The previous prime is 1221222020983. The next prime is 1221222021121. The reversal of 1221222021021 is 1201202221221.

It is a happy number.

1221222021021 is a `hidden beast` number, since 1 + 2 + 212 + 220 + 210 + 21 = 666.

It is not a de Polignac number, because 1221222021021 - 2⁹ = 1221222020509 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221222020985 and 1221222021003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221222021121) 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, 22615222585 + ... + 22615222638.

It is an arithmetic number, because the mean of its divisors is an integer number (226152226120).

Almost surely, 2^{1221222021021} is an apocalyptic number.

It is an amenable number.

1221222021021 is a deficient number, since it is larger than the sum of its proper divisors (587995787939).

1221222021021 is an equidigital number, since it uses as much as digits as its factorization.

1221222021021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45230445232 (or 45230445226 counting only the distinct ones).

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

Adding to 1221222021021 its reverse (1201202221221), we get a palindrome (2422424242242).

The spelling of 1221222021021 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-two million, twenty-one thousand, twenty-one".