21001120101221 has 16 divisors (see below), whose sum is σ = 22786900725120. Its totient is φ = 19239901012800.

The previous prime is 21001120101193. The next prime is 21001120101223. The reversal of 21001120101221 is 12210102110012.

It is not a de Polignac number, because 21001120101221 - 2¹⁴ = 21001120084837 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21001120101196 and 21001120101205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001120101223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2646515 + ... + 7000448.

It is an arithmetic number, because the mean of its divisors is an integer number (1424181295320).

Almost surely, 2^{21001120101221} is an apocalyptic number.

It is an amenable number.

21001120101221 is a deficient number, since it is larger than the sum of its proper divisors (1785780623899).

21001120101221 is a wasteful number, since it uses less digits than its factorization.

21001120101221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9648236.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21001120101221 its reverse (12210102110012), we get a palindrome (33211222211233).

The spelling of 21001120101221 in words is "twenty-one trillion, one billion, one hundred twenty million, one hundred one thousand, two hundred twenty-one".