21021100213 has 4 divisors (see below), whose sum is σ = 21021733548. Its totient is φ = 21020466880.

The previous prime is 21021100211. The next prime is 21021100231. The reversal of 21021100213 is 31200112012.

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 16263135729 + 4757964484 = 127527^2 + 68978^2 .

It is a cyclic number.

It is not a de Polignac number, because 21021100213 - 2¹ = 21021100211 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21021100193 and 21021100202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021100211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 263956 + ... + 334237.

It is an arithmetic number, because the mean of its divisors is an integer number (5255433387).

Almost surely, 2^21021100213 is an apocalyptic number.

It is an amenable number.

21021100213 is a deficient number, since it is larger than the sum of its proper divisors (633335).

21021100213 is an equidigital number, since it uses as much as digits as its factorization.

21021100213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 633334.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21021100213 its reverse (31200112012), we get a palindrome (52221212225).

The spelling of 21021100213 in words is "twenty-one billion, twenty-one million, one hundred thousand, two hundred thirteen".