21221101002001 has 2 divisors, whose sum is σ = 21221101002002. Its totient is φ = 21221101002000.

The previous prime is 21221101001981. The next prime is 21221101002047. The reversal of 21221101002001 is 10020010112212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18681205374976 + 2539895627025 = 4322176^2 + 1593705^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221101002001 - 2²³ = 21221092613393 is a prime.

It is not a weakly prime, because it can be changed into another prime (21221101002401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610550501000 + 10610550501001.

It is an arithmetic number, because the mean of its divisors is an integer number (10610550501001).

Almost surely, 2^{21221101002001} is an apocalyptic number.

It is an amenable number.

21221101002001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221101002001 is an equidigital number, since it uses as much as digits as its factorization.

21221101002001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21221101002001 its reverse (10020010112212), we get a palindrome (31241111114213).

The spelling of 21221101002001 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred one million, two thousand, one".