21120212001221 has 16 divisors (see below), whose sum is σ = 21665338204608. Its totient is φ = 20576520451200.

The previous prime is 21120212001193. The next prime is 21120212001307. The reversal of 21120212001221 is 12210021202112.

It is a cyclic number.

It is not a de Polignac number, because 21120212001221 - 2⁶ = 21120212001157 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21120212001221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120212007221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 320733326 + ... + 320799168.

It is an arithmetic number, because the mean of its divisors is an integer number (1354083637788).

Almost surely, 2^{21120212001221} is an apocalyptic number.

It is an amenable number.

21120212001221 is a deficient number, since it is larger than the sum of its proper divisors (545126203387).

21120212001221 is an equidigital number, since it uses as much as digits as its factorization.

21120212001221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76612.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21120212001221 its reverse (12210021202112), we get a palindrome (33330233203333).

The spelling of 21120212001221 in words is "twenty-one trillion, one hundred twenty billion, two hundred twelve million, one thousand, two hundred twenty-one".