21002001122001 has 16 divisors (see below), whose sum is σ = 28017185040000. Its totient is φ = 13994076125568.

The previous prime is 21002001121999. The next prime is 21002001122009. The reversal of 21002001122001 is 10022110020012.

It is not a de Polignac number, because 21002001122001 - 2¹ = 21002001121999 is a prime.

It is a super-2 number, since 2×21002001122001² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21002001122009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 295771500 + ... + 295842498.

It is an arithmetic number, because the mean of its divisors is an integer number (1751074065000).

Almost surely, 2^{21002001122001} is an apocalyptic number.

It is an amenable number.

21002001122001 is a deficient number, since it is larger than the sum of its proper divisors (7015183917999).

21002001122001 is a wasteful number, since it uses less digits than its factorization.

21002001122001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120728.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21002001122001 its reverse (10022110020012), we get a palindrome (31024111142013).

The spelling of 21002001122001 in words is "twenty-one trillion, two billion, one million, one hundred twenty-two thousand, one".