21011213131021 has 2 divisors, whose sum is σ = 21011213131022. Its totient is φ = 21011213131020.

The previous prime is 21011213131019. The next prime is 21011213131037. The reversal of 21011213131021 is 12013131211012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15805792922500 + 5205420208521 = 3975650^2 + 2281539^2 .

It is a cyclic number.

It is not a de Polignac number, because 21011213131021 - 2¹ = 21011213131019 is a prime.

It is a super-2 number, since 2×21011213131021² (a number of 27 digits) contains 22 as substring.

Together with 21011213131019, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21011213131021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21011213831021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505606565510 + 10505606565511.

It is an arithmetic number, because the mean of its divisors is an integer number (10505606565511).

Almost surely, 2^{21011213131021} is an apocalyptic number.

It is an amenable number.

21011213131021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011213131021 is an equidigital number, since it uses as much as digits as its factorization.

21011213131021 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 19.

Adding to 21011213131021 its reverse (12013131211012), we get a palindrome (33024344342033).

The spelling of 21011213131021 in words is "twenty-one trillion, eleven billion, two hundred thirteen million, one hundred thirty-one thousand, twenty-one".