21220121002001 has 2 divisors, whose sum is σ = 21220121002002. Its totient is φ = 21220121002000.

The previous prime is 21220121001979. The next prime is 21220121002009. The reversal of 21220121002001 is 10020012102212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20465309299600 + 754811702401 = 4523860^2 + 868799^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21220121002001 is a prime.

It is a super-4 number, since 4×21220121002001⁴ (a number of 54 digits) contains 4444 as substring.

It is not a weakly prime, because it can be changed into another prime (21220121002009) 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 as a sum of consecutive naturals, namely, 10610060501000 + 10610060501001.

It is an arithmetic number, because the mean of its divisors is an integer number (10610060501001).

Almost surely, 2^{21220121002001} is an apocalyptic number.

It is an amenable number.

21220121002001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220121002001 is an equidigital number, since it uses as much as digits as its factorization.

21220121002001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21220121002001 its reverse (10020012102212), we get a palindrome (31240133104213).

The spelling of 21220121002001 in words is "twenty-one trillion, two hundred twenty billion, one hundred twenty-one million, two thousand, one".