21112211212021 has 16 divisors (see below), whose sum is σ = 23053583750400. Its totient is φ = 19266209164800.

The previous prime is 21112211211997. The next prime is 21112211212031. The reversal of 21112211212021 is 12021211221112.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21112211212021 - 2¹⁷ = 21112211080949 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21112211212021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112211212031) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 171468100 + ... + 171591181.

It is an arithmetic number, because the mean of its divisors is an integer number (1440848984400).

Almost surely, 2^{21112211212021} is an apocalyptic number.

It is an amenable number.

21112211212021 is a deficient number, since it is larger than the sum of its proper divisors (1941372538379).

21112211212021 is a wasteful number, since it uses less digits than its factorization.

21112211212021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343059420.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21112211212021 its reverse (12021211221112), we get a palindrome (33133422433133).

Subtracting from 21112211212021 its reverse (12021211221112), we obtain a palindrome (9090999990909).

The spelling of 21112211212021 in words is "twenty-one trillion, one hundred twelve billion, two hundred eleven million, two hundred twelve thousand, twenty-one".