21210131111321 has 2 divisors, whose sum is σ = 21210131111322. Its totient is φ = 21210131111320.

The previous prime is 21210131111317. The next prime is 21210131111327. The reversal of 21210131111321 is 12311113101212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20984828046400 + 225303064921 = 4580920^2 + 474661^2 .

It is a cyclic number.

It is not a de Polignac number, because 21210131111321 - 2² = 21210131111317 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21210131111293 and 21210131111302.

It is not a weakly prime, because it can be changed into another prime (21210131111327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605065555660 + 10605065555661.

It is an arithmetic number, because the mean of its divisors is an integer number (10605065555661).

Almost surely, 2^{21210131111321} is an apocalyptic number.

It is an amenable number.

21210131111321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210131111321 is an equidigital number, since it uses as much as digits as its factorization.

21210131111321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 20.

Adding to 21210131111321 its reverse (12311113101212), we get a palindrome (33521244212533).

The spelling of 21210131111321 in words is "twenty-one trillion, two hundred ten billion, one hundred thirty-one million, one hundred eleven thousand, three hundred twenty-one".