21123013213 has 16 divisors (see below), whose sum is σ = 23711007744. Its totient is φ = 18719182080.

The previous prime is 21123013193. The next prime is 21123013267. The reversal of 21123013213 is 31231032112.

It is a de Polignac number, because none of the positive numbers 2^k-21123013213 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 (21123013283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 522145 + ... + 561142.

It is an arithmetic number, because the mean of its divisors is an integer number (1481937984).

Almost surely, 2^21123013213 is an apocalyptic number.

It is an amenable number.

21123013213 is a deficient number, since it is larger than the sum of its proper divisors (2587994531).

21123013213 is a wasteful number, since it uses less digits than its factorization.

21123013213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1083372.

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

Adding to 21123013213 its reverse (31231032112), we get a palindrome (52354045325).

The spelling of 21123013213 in words is "twenty-one billion, one hundred twenty-three million, thirteen thousand, two hundred thirteen".