21212020201121 has 2 divisors, whose sum is σ = 21212020201122. Its totient is φ = 21212020201120.

The previous prime is 21212020201117. The next prime is 21212020201147. The reversal of 21212020201121 is 12110202021212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13088585374225 + 8123434826896 = 3617815^2 + 2850164^2 .

It is a cyclic number.

It is not a de Polignac number, because 21212020201121 - 2² = 21212020201117 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21212020201121.

It is not a weakly prime, because it can be changed into another prime (21212020200121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606010100560 + 10606010100561.

It is an arithmetic number, because the mean of its divisors is an integer number (10606010100561).

Almost surely, 2^{21212020201121} is an apocalyptic number.

It is an amenable number.

21212020201121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212020201121 is an equidigital number, since it uses as much as digits as its factorization.

21212020201121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21212020201121 its reverse (12110202021212), we get a palindrome (33322222222333).

The spelling of 21212020201121 in words is "twenty-one trillion, two hundred twelve billion, twenty million, two hundred one thousand, one hundred twenty-one".