20001003821 has 2 divisors, whose sum is σ = 20001003822. Its totient is φ = 20001003820.

The previous prime is 20001003811. The next prime is 20001003839. The reversal of 20001003821 is 12830010002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17268850921 + 2732152900 = 131411^2 + 52270^2 .

It is a cyclic number.

It is not a de Polignac number, because 20001003821 - 2²⁶ = 19933894957 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20001003821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20001003811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10000501910 + 10000501911.

It is an arithmetic number, because the mean of its divisors is an integer number (10000501911).

Almost surely, 2^20001003821 is an apocalyptic number.

It is an amenable number.

20001003821 is a deficient number, since it is larger than the sum of its proper divisors (1).

20001003821 is an equidigital number, since it uses as much as digits as its factorization.

20001003821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 20001003821 its reverse (12830010002), we get a palindrome (32831013823).

The spelling of 20001003821 in words is "twenty billion, one million, three thousand, eight hundred twenty-one".