1002200021 has 4 divisors (see below), whose sum is σ = 1005402252. Its totient is φ = 998997792.

The previous prime is 1002199987. The next prime is 1002200029. The reversal of 1002200021 is 1200022001.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 86229796 + 915970225 = 9286^2 + 30265^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1002200021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1002199981 and 1002200008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1002200029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1600646 + ... + 1601271.

It is an arithmetic number, because the mean of its divisors is an integer number (251350563).

Almost surely, 2^1002200021 is an apocalyptic number.

It is an amenable number.

1002200021 is a deficient number, since it is larger than the sum of its proper divisors (3202231).

1002200021 is an equidigital number, since it uses as much as digits as its factorization.

1002200021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3202230.

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

The square root of 1002200021 is about 31657.5428768564. The cubic root of 1002200021 is about 1000.7328032016.

Adding to 1002200021 its reverse (1200022001), we get a palindrome (2202222022).

The spelling of 1002200021 in words is "one billion, two million, two hundred thousand, twenty-one".