2002122100021 has 4 divisors (see below), whose sum is σ = 2010429660844. Its totient is φ = 1993814539200.

The previous prime is 2002122100019. The next prime is 2002122100039. The reversal of 2002122100021 is 1200012212002.

It is a happy number.

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 1817467978225 + 184654121796 = 1348135^2 + 429714^2 .

It is a cyclic number.

It is not a de Polignac number, because 2002122100021 - 2¹ = 2002122100019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2002122099974 and 2002122100010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2002122100091) 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, 4153780050 + ... + 4153780531.

It is an arithmetic number, because the mean of its divisors is an integer number (502607415211).

Almost surely, 2^{2002122100021} is an apocalyptic number.

It is an amenable number.

2002122100021 is a deficient number, since it is larger than the sum of its proper divisors (8307560823).

2002122100021 is an equidigital number, since it uses as much as digits as its factorization.

2002122100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8307560822.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 2002122100021 its reverse (1200012212002), we get a palindrome (3202134312023).

The spelling of 2002122100021 in words is "two trillion, two billion, one hundred twenty-two million, one hundred thousand, twenty-one".