2101000021 has 8 divisors (see below), whose sum is σ = 2200504320. Its totient is φ = 2002175472.

The previous prime is 2101000007. The next prime is 2101000037. The reversal of 2101000021 is 1200001012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2101000021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2100999968 and 2101000013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2101000061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 163605 + ... + 175978.

It is an arithmetic number, because the mean of its divisors is an integer number (275063040).

Almost surely, 2^2101000021 is an apocalyptic number.

It is an amenable number.

2101000021 is a deficient number, since it is larger than the sum of its proper divisors (99504299).

2101000021 is a wasteful number, since it uses less digits than its factorization.

2101000021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 339875.

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 2101000021 is about 45836.6667745376. Note that the first 3 decimals coincide. The cubic root of 2101000021 is about 1280.7824035329.

Adding to 2101000021 its reverse (1200001012), we get a palindrome (3301001033).

Subtracting from 2101000021 its reverse (1200001012), we obtain a palindrome (900999009).

The spelling of 2101000021 in words is "two billion, one hundred one million, twenty-one", and thus it is an aban number.