21000211101221 has 32 divisors (see below), whose sum is σ = 23303628288000. Its totient is φ = 18765435386880.

The previous prime is 21000211101197. The next prime is 21000211101227. The reversal of 21000211101221 is 12210111200012.

It is a cyclic number.

It is not a de Polignac number, because 21000211101221 - 2²⁶ = 21000143992357 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21000211101196 and 21000211101205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000211101227) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 402361595 + ... + 402413783.

It is an arithmetic number, because the mean of its divisors is an integer number (728238384000).

Almost surely, 2^{21000211101221} is an apocalyptic number.

It is an amenable number.

21000211101221 is a deficient number, since it is larger than the sum of its proper divisors (2303417186779).

21000211101221 is a wasteful number, since it uses less digits than its factorization.

21000211101221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54989.

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

Adding to 21000211101221 its reverse (12210111200012), we get a palindrome (33210322301233).

The spelling of 21000211101221 in words is "twenty-one trillion, two hundred eleven million, one hundred one thousand, two hundred twenty-one".