21211301221 has 8 divisors (see below), whose sum is σ = 23160785184. Its totient is φ = 19265347920.

The previous prime is 21211301197. The next prime is 21211301227. The reversal of 21211301221 is 12210311212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21211301221 - 2¹⁵ = 21211268453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21211301195 and 21211301204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211301227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 870091 + ... + 894136.

It is an arithmetic number, because the mean of its divisors is an integer number (2895098148).

Almost surely, 2^21211301221 is an apocalyptic number.

It is an amenable number.

21211301221 is a deficient number, since it is larger than the sum of its proper divisors (1949483963).

21211301221 is a wasteful number, since it uses less digits than its factorization.

21211301221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1765331.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 21211301221 its reverse (12210311212), we get a palindrome (33421612433).

Subtracting from 21211301221 its reverse (12210311212), we obtain a palindrome (9000990009).

The spelling of 21211301221 in words is "twenty-one billion, two hundred eleven million, three hundred one thousand, two hundred twenty-one".