21111211121021 has 8 divisors (see below), whose sum is σ = 24137080693440. Its totient is φ = 18087837115968.

The previous prime is 21111211120999. The next prime is 21111211121027. The reversal of 21111211121021 is 12012111211112.

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 21111211121021 - 2²² = 21111206926717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111211121027) 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, 623873711 + ... + 623907548.

It is an arithmetic number, because the mean of its divisors is an integer number (3017135086680).

Almost surely, 2^{21111211121021} is an apocalyptic number.

It is an amenable number.

21111211121021 is a deficient number, since it is larger than the sum of its proper divisors (3025869572419).

21111211121021 is a wasteful number, since it uses less digits than its factorization.

21111211121021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1247783683.

The product of its (nonzero) digits is 16, while the sum is 17.

Adding to 21111211121021 its reverse (12012111211112), we get a palindrome (33123322332133).

Subtracting from 21111211121021 its reverse (12012111211112), we obtain a palindrome (9099099909909).

The spelling of 21111211121021 in words is "twenty-one trillion, one hundred eleven billion, two hundred eleven million, one hundred twenty-one thousand, twenty-one".