21221202121001 has 2 divisors, whose sum is σ = 21221202121002. Its totient is φ = 21221202121000.

The previous prime is 21221202120971. The next prime is 21221202121033. The reversal of 21221202121001 is 10012120212212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20907939150400 + 313262970601 = 4572520^2 + 559699^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221202121001 - 2²² = 21221197926697 is a prime.

It is not a weakly prime, because it can be changed into another prime (21221202121081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610601060500 + 10610601060501.

It is an arithmetic number, because the mean of its divisors is an integer number (10610601060501).

Almost surely, 2^{21221202121001} is an apocalyptic number.

It is an amenable number.

21221202121001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221202121001 is an equidigital number, since it uses as much as digits as its factorization.

21221202121001 is an evil number, because the sum of its binary digits is even.

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

Adding to 21221202121001 its reverse (10012120212212), we get a palindrome (31233322333213).

The spelling of 21221202121001 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred two million, one hundred twenty-one thousand, one".