21210111321 has 16 divisors (see below), whose sum is σ = 33434659200. Its totient is φ = 11702130048.

The previous prime is 21210111311. The next prime is 21210111337. The reversal of 21210111321 is 12311101212.

It is not a de Polignac number, because 21210111321 - 2⁵ = 21210111289 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21210111321.

It is not an unprimeable number, because it can be changed into a prime (21210111311) 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 15 ways as a sum of consecutive naturals, for example, 17413276 + ... + 17414493.

It is an arithmetic number, because the mean of its divisors is an integer number (2089666200).

Almost surely, 2^21210111321 is an apocalyptic number.

21210111321 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21210111321 is a deficient number, since it is larger than the sum of its proper divisors (12224547879).

21210111321 is a wasteful number, since it uses less digits than its factorization.

21210111321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34827808.

The product of its (nonzero) digits is 24, while the sum is 15.

Adding to 21210111321 its reverse (12311101212), we get a palindrome (33521212533).

The spelling of 21210111321 in words is "twenty-one billion, two hundred ten million, one hundred eleven thousand, three hundred twenty-one".