21112102021 has 8 divisors (see below), whose sum is σ = 21462656600. Its totient is φ = 20763205632.

The previous prime is 21112102007. The next prime is 21112102027. The reversal of 21112102021 is 12020121112.

It can be written as a sum of positive squares in 4 ways, for example, as 2380073796 + 18732028225 = 48786^2 + 136865^2 .

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 21112102021 - 2¹⁷ = 21111970949 is a prime.

It is a super-2 number, since 2×21112102021² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21112101992 and 21112102010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112102027) 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, 388860 + ... + 439813.

It is an arithmetic number, because the mean of its divisors is an integer number (2682832075).

Almost surely, 2^21112102021 is an apocalyptic number.

It is an amenable number.

21112102021 is a deficient number, since it is larger than the sum of its proper divisors (350554579).

21112102021 is an equidigital number, since it uses as much as digits as its factorization.

21112102021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 829095.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21112102021 its reverse (12020121112), we get a palindrome (33132223133).

The spelling of 21112102021 in words is "twenty-one billion, one hundred twelve million, one hundred two thousand, twenty-one".