210001200021 has 16 divisors (see below), whose sum is σ = 311304880320. Its totient is φ = 139914403920.

The previous prime is 210001200001. The next prime is 210001200043. The reversal of 210001200021 is 120002100012.

It is not a de Polignac number, because 210001200021 - 2²² = 209997005717 is a prime.

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

It is a junction number, because it is equal to n+sod(n) for n = 210001199976 and 210001200012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210001200001) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2355315 + ... + 2442848.

It is an arithmetic number, because the mean of its divisors is an integer number (19456555020).

Almost surely, 2^210001200021 is an apocalyptic number.

It is an amenable number.

210001200021 is a deficient number, since it is larger than the sum of its proper divisors (101303680299).

210001200021 is a wasteful number, since it uses less digits than its factorization.

210001200021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4799793 (or 4799787 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 210001200021 its reverse (120002100012), we get a palindrome (330003300033).

The spelling of 210001200021 in words is "two hundred ten billion, one million, two hundred thousand, twenty-one".