1221022120021 has 64 divisors (see below), whose sum is σ = 1395559756800. Its totient is φ = 1067603328000.

The previous prime is 1221022119959. The next prime is 1221022120027. The reversal of 1221022120021 is 1200212201221.

It is a happy number.

It is not a de Polignac number, because 1221022120021 - 2⁷ = 1221022119893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221022119977 and 1221022120004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221022120027) 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, 941419645 + ... + 941420941.

It is an arithmetic number, because the mean of its divisors is an integer number (21805621200).

Almost surely, 2^{1221022120021} is an apocalyptic number.

1221022120021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221022120021 is a deficient number, since it is larger than the sum of its proper divisors (174537636779).

1221022120021 is a wasteful number, since it uses less digits than its factorization.

1221022120021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1627 (or 1605 counting only the distinct ones).

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

Adding to 1221022120021 its reverse (1200212201221), we get a palindrome (2421234321242).

The spelling of 1221022120021 in words is "one trillion, two hundred twenty-one billion, twenty-two million, one hundred twenty thousand, twenty-one".