21111010211221 has 8 divisors (see below), whose sum is σ = 24251878497344. Its totient is φ = 18001394346240.

The previous prime is 21111010211201. The next prime is 21111010211227. The reversal of 21111010211221 is 12211201011112.

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 21111010211221 - 2²³ = 21111001822613 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21111010211195 and 21111010211204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111010211227) 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, 7813103835 + ... + 7813106536.

It is an arithmetic number, because the mean of its divisors is an integer number (3031484812168).

Almost surely, 2^{21111010211221} is an apocalyptic number.

It is an amenable number.

21111010211221 is a deficient number, since it is larger than the sum of its proper divisors (3140868286123).

21111010211221 is a wasteful number, since it uses less digits than its factorization.

21111010211221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15626210571.

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

Adding to 21111010211221 its reverse (12211201011112), we get a palindrome (33322211222333).

The spelling of 21111010211221 in words is "twenty-one trillion, one hundred eleven billion, ten million, two hundred eleven thousand, two hundred twenty-one".