2001123100021 has 2 divisors, whose sum is σ = 2001123100022. Its totient is φ = 2001123100020.

The previous prime is 2001123100003. The next prime is 2001123100043. The reversal of 2001123100021 is 1200013211002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1729514312100 + 271608787921 = 1315110^2 + 521161^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001123100021 - 2²¹ = 2001121002869 is a prime.

It is a super-2 number, since 2×2001123100021² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 2001123099974 and 2001123100010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2001123100091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1000561550010 + 1000561550011.

It is an arithmetic number, because the mean of its divisors is an integer number (1000561550011).

Almost surely, 2^{2001123100021} is an apocalyptic number.

It is an amenable number.

2001123100021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001123100021 is an equidigital number, since it uses as much as digits as its factorization.

2001123100021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 2001123100021 its reverse (1200013211002), we get a palindrome (3201136311023).

The spelling of 2001123100021 in words is "two trillion, one billion, one hundred twenty-three million, one hundred thousand, twenty-one".