21112210111021 has 16 divisors (see below), whose sum is σ = 22457998070640. Its totient is φ = 19778047672320.

The previous prime is 21112210110949. The next prime is 21112210111033. The reversal of 21112210111021 is 12011101221112.

It can be written as a sum of positive squares in 8 ways, for example, as 11739189062500 + 9373021048521 = 3426250^2 + 3061539^2 .

It is not a de Polignac number, because 21112210111021 - 2³⁵ = 21077850372653 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21112210110986 and 21112210111004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112210121021) 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, 6986235 + ... + 9541063.

It is an arithmetic number, because the mean of its divisors is an integer number (1403624879415).

Almost surely, 2^{21112210111021} is an apocalyptic number.

It is an amenable number.

21112210111021 is a deficient number, since it is larger than the sum of its proper divisors (1345787959619).

21112210111021 is a wasteful number, since it uses less digits than its factorization.

21112210111021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2557104.

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

Adding to 21112210111021 its reverse (12011101221112), we get a palindrome (33123311332133).

The spelling of 21112210111021 in words is "twenty-one trillion, one hundred twelve billion, two hundred ten million, one hundred eleven thousand, twenty-one".