20005021 has 2 divisors, whose sum is σ = 20005022. Its totient is φ = 20005020.

The previous prime is 20005003. The next prime is 20005087. The reversal of 20005021 is 12050002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16924996 + 3080025 = 4114^2 + 1755^2 .

It is a cyclic number.

It is not a de Polignac number, because 20005021 - 2⁷ = 20004893 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20004989 and 20005007.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20005721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10002510 + 10002511.

It is an arithmetic number, because the mean of its divisors is an integer number (10002511).

Almost surely, 2^20005021 is an apocalyptic number.

It is an amenable number.

20005021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20005021 is an equidigital number, since it uses as much as digits as its factorization.

20005021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20, while the sum is 10.

The square root of 20005021 is about 4472.6972846371. The cubic root of 20005021 is about 271.4644749103.

Adding to 20005021 its reverse (12050002), we get a palindrome (32055023).

It can be divided in two parts, 2000 and 5021, that added together give a triangular number (7021 = T₁₁₈).

The spelling of 20005021 in words is "twenty million, five thousand, twenty-one".