21121100213 has 4 divisors (see below), whose sum is σ = 21123233100. Its totient is φ = 21118967328.

The previous prime is 21121100173. The next prime is 21121100227. The reversal of 21121100213 is 31200112112.

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 7900009924 + 13221090289 = 88882^2 + 114983^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121100213 - 2¹⁰ = 21121099189 is a prime.

It is a super-2 number, since 2×21121100213² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121100243) 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, 1051520 + ... + 1071417.

It is an arithmetic number, because the mean of its divisors is an integer number (5280808275).

Almost surely, 2^21121100213 is an apocalyptic number.

It is an amenable number.

21121100213 is a deficient number, since it is larger than the sum of its proper divisors (2132887).

21121100213 is an equidigital number, since it uses as much as digits as its factorization.

21121100213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2132886.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21121100213 its reverse (31200112112), we get a palindrome (52321212325).

The spelling of 21121100213 in words is "twenty-one billion, one hundred twenty-one million, one hundred thousand, two hundred thirteen".