21002121100001 has 2 divisors, whose sum is σ = 21002121100002. Its totient is φ = 21002121100000.

The previous prime is 21002121099923. The next prime is 21002121100007. The reversal of 21002121100001 is 10000112120012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13542400000000 + 7459721100001 = 3680000^2 + 2731249^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002121100001 - 2³⁸ = 20727243193057 is a prime.

It is not a weakly prime, because it can be changed into another prime (21002121100007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501060550000 + 10501060550001.

It is an arithmetic number, because the mean of its divisors is an integer number (10501060550001).

Almost surely, 2^{21002121100001} is an apocalyptic number.

It is an amenable number.

21002121100001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002121100001 is an equidigital number, since it uses as much as digits as its factorization.

21002121100001 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 11.

Adding to 21002121100001 its reverse (10000112120012), we get a palindrome (31002233220013).

The spelling of 21002121100001 in words is "twenty-one trillion, two billion, one hundred twenty-one million, one hundred thousand, one".