21002001100101 has 24 divisors (see below), whose sum is σ = 35377520484800. Its totient is φ = 12001143484008.

The previous prime is 21002001100027. The next prime is 21002001100103. The reversal of 21002001100101 is 10100110020012.

It is a happy number.

It is not a de Polignac number, because 21002001100101 - 2¹⁰ = 21002001099077 is a prime.

It is a super-2 number, since 2×21002001100101² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002001100103) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3401681575 + ... + 3401687748.

Almost surely, 2^{21002001100101} is an apocalyptic number.

21002001100101 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21002001100101 is a deficient number, since it is larger than the sum of its proper divisors (14375519384699).

21002001100101 is an equidigital number, since it uses as much as digits as its factorization.

21002001100101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6803369350 (or 6803369333 counting only the distinct ones).

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

Adding to 21002001100101 its reverse (10100110020012), we get a palindrome (31102111120113).

The spelling of 21002001100101 in words is "twenty-one trillion, two billion, one million, one hundred thousand, one hundred one".