21001101020001 has 6 divisors (see below), whose sum is σ = 30334923695570. Its totient is φ = 14000734013328.

The previous prime is 21001101019901. The next prime is 21001101020033. The reversal of 21001101020001 is 10002010110012.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20977096165776 + 24004854225 = 4580076^2 + 154935^2 .

It is not a de Polignac number, because 21001101020001 - 2²¹ = 21001098922849 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 2333455668889 = 21001101020001 / (2 + 1 + 0 + 0 + 1 + 1 + 0 + 1 + 0 + 2 + 0 + 0 + 0 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21001101020201) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1166727834436 + ... + 1166727834453.

Almost surely, 2^{21001101020001} is an apocalyptic number.

It is an amenable number.

21001101020001 is a deficient number, since it is larger than the sum of its proper divisors (9333822675569).

21001101020001 is a wasteful number, since it uses less digits than its factorization.

21001101020001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2333455668895 (or 2333455668892 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21001101020001 its reverse (10002010110012), we get a palindrome (31003111130013).

The spelling of 21001101020001 in words is "twenty-one trillion, one billion, one hundred one million, twenty thousand, one".