21111101010221 has 4 divisors (see below), whose sum is σ = 21602056847712. Its totient is φ = 20620145172732.

The previous prime is 21111101010217. The next prime is 21111101010227. The reversal of 21111101010221 is 12201010111112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21111101010221 - 2² = 21111101010217 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21111101010196 and 21111101010205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111101010227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 245477918681 + ... + 245477918766.

It is an arithmetic number, because the mean of its divisors is an integer number (5400514211928).

Almost surely, 2^{21111101010221} is an apocalyptic number.

It is an amenable number.

21111101010221 is a deficient number, since it is larger than the sum of its proper divisors (490955837491).

21111101010221 is an equidigital number, since it uses as much as digits as its factorization.

21111101010221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 490955837490.

The product of its (nonzero) digits is 8, while the sum is 14.

Adding to 21111101010221 its reverse (12201010111112), we get a palindrome (33312111121333).

The spelling of 21111101010221 in words is "twenty-one trillion, one hundred eleven billion, one hundred one million, ten thousand, two hundred twenty-one".