21120021221221 has 48 divisors (see below), whose sum is σ = 24293840062464. Its totient is φ = 18242429812992.

The previous prime is 21120021221213. The next prime is 21120021221237. The reversal of 21120021221221 is 12212212002112.

It is not a de Polignac number, because 21120021221221 - 2³ = 21120021221213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120021221291) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 742419820 + ... + 742448266.

It is an arithmetic number, because the mean of its divisors is an integer number (506121667968).

Almost surely, 2^{21120021221221} is an apocalyptic number.

It is an amenable number.

21120021221221 is a deficient number, since it is larger than the sum of its proper divisors (3173818841243).

21120021221221 is a wasteful number, since it uses less digits than its factorization.

21120021221221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30850 (or 30827 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 21120021221221 its reverse (12212212002112), we get a palindrome (33332233223333).

The spelling of 21120021221221 in words is "twenty-one trillion, one hundred twenty billion, twenty-one million, two hundred twenty-one thousand, two hundred twenty-one".