21123310213 has 6 divisors (see below), whose sum is σ = 21487404134. Its totient is φ = 20765284584.

The previous prime is 21123310199. The next prime is 21123310253. The reversal of 21123310213 is 31201332112.

It can be written as a sum of positive squares in only one way, i.e., 20100717729 + 1022592484 = 141777^2 + 31978^2 .

It is not a de Polignac number, because 21123310213 - 2¹⁷ = 21123179141 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21123310253) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3030606 + ... + 3037567.

Almost surely, 2^21123310213 is an apocalyptic number.

It is an amenable number.

21123310213 is a deficient number, since it is larger than the sum of its proper divisors (364093921).

21123310213 is an frugal number, since it uses more digits than its factorization.

21123310213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6068291 (or 6068232 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 21123310213 its reverse (31201332112), we get a palindrome (52324642325).

The spelling of 21123310213 in words is "twenty-one billion, one hundred twenty-three million, three hundred ten thousand, two hundred thirteen".