21121212022021 has 2 divisors, whose sum is σ = 21121212022022. Its totient is φ = 21121212022020.

The previous prime is 21121212021997. The next prime is 21121212022061. The reversal of 21121212022021 is 12022021212112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15073891665121 + 6047320356900 = 3882511^2 + 2459130^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121212022021 - 2⁷ = 21121212021893 is a prime.

It is a super-2 number, since 2×21121212022021² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21121212022021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21121212022061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560606011010 + 10560606011011.

It is an arithmetic number, because the mean of its divisors is an integer number (10560606011011).

Almost surely, 2^{21121212022021} is an apocalyptic number.

It is an amenable number.

21121212022021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121212022021 is an equidigital number, since it uses as much as digits as its factorization.

21121212022021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 21121212022021 its reverse (12022021212112), we get a palindrome (33143233234133).

The spelling of 21121212022021 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twelve million, twenty-two thousand, twenty-one".