21112201021 has 4 divisors (see below), whose sum is σ = 21114819100. Its totient is φ = 21109582944.

The previous prime is 21112201013. The next prime is 21112201027. The reversal of 21112201021 is 12010221112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11169319225 + 9942881796 = 105685^2 + 99714^2 .

It is a cyclic number.

It is not a de Polignac number, because 21112201021 - 2³ = 21112201013 is a prime.

It is a super-2 number, since 2×21112201021² (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 = 21112200992 and 21112201010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112201027) 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, 1296906 + ... + 1313083.

It is an arithmetic number, because the mean of its divisors is an integer number (5278704775).

Almost surely, 2^21112201021 is an apocalyptic number.

It is an amenable number.

21112201021 is a deficient number, since it is larger than the sum of its proper divisors (2618079).

21112201021 is an equidigital number, since it uses as much as digits as its factorization.

21112201021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2618078.

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

Adding to 21112201021 its reverse (12010221112), we get a palindrome (33122422133).

The spelling of 21112201021 in words is "twenty-one billion, one hundred twelve million, two hundred one thousand, twenty-one".