21001112005001 has 2 divisors, whose sum is σ = 21001112005002. Its totient is φ = 21001112005000.

The previous prime is 21001112004997. The next prime is 21001112005043. The reversal of 21001112005001 is 10050021110012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15474381195001 + 5526730810000 = 3933749^2 + 2350900^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001112005001 - 2² = 21001112004997 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21001112025001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500556002500 + 10500556002501.

It is an arithmetic number, because the mean of its divisors is an integer number (10500556002501).

Almost surely, 2^{21001112005001} is an apocalyptic number.

It is an amenable number.

21001112005001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001112005001 is an equidigital number, since it uses as much as digits as its factorization.

21001112005001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20, while the sum is 14.

Adding to 21001112005001 its reverse (10050021110012), we get a palindrome (31051133115013).

The spelling of 21001112005001 in words is "twenty-one trillion, one billion, one hundred twelve million, five thousand, one".