1221022221021 has 64 divisors (see below), whose sum is σ = 1873274618880. Its totient is φ = 785505600000.

The previous prime is 1221022220983. The next prime is 1221022221049. The reversal of 1221022221021 is 1201222201221.

It is a happy number.

1221022221021 is a `hidden beast` number, since 1 + 2 + 210 + 222 + 210 + 21 = 666.

It is not a de Polignac number, because 1221022221021 - 2¹⁷ = 1221022089949 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221022220985 and 1221022221003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221022221091) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 123318171 + ... + 123328071.

It is an arithmetic number, because the mean of its divisors is an integer number (29269915920).

Almost surely, 2^{1221022221021} is an apocalyptic number.

It is an amenable number.

1221022221021 is a deficient number, since it is larger than the sum of its proper divisors (652252397859).

1221022221021 is a wasteful number, since it uses less digits than its factorization.

1221022221021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11155 (or 11149 counting only the distinct ones).

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

Adding to 1221022221021 its reverse (1201222201221), we get a palindrome (2422244422242).

The spelling of 1221022221021 in words is "one trillion, two hundred twenty-one billion, twenty-two million, two hundred twenty-one thousand, twenty-one".