21001020102001 has 2 divisors, whose sum is σ = 21001020102002. Its totient is φ = 21001020102000.

The previous prime is 21001020101989. The next prime is 21001020102071. The reversal of 21001020102001 is 10020102010012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19253008230625 + 1748011871376 = 4387825^2 + 1322124^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001020102001 - 2²⁷ = 21000885884273 is a prime.

It is not a weakly prime, because it can be changed into another prime (21001020102071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500510051000 + 10500510051001.

It is an arithmetic number, because the mean of its divisors is an integer number (10500510051001).

Almost surely, 2^{21001020102001} is an apocalyptic number.

It is an amenable number.

21001020102001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001020102001 is an equidigital number, since it uses as much as digits as its factorization.

21001020102001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21001020102001 its reverse (10020102010012), we get a palindrome (31021122112013).

The spelling of 21001020102001 in words is "twenty-one trillion, one billion, twenty million, one hundred two thousand, one".