8521021 has 2 divisors, whose sum is σ = 8521022. Its totient is φ = 8521020.

The previous prime is 8521013. The next prime is 8521061. The reversal of 8521021 is 1201258.

8521021 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8352100 + 168921 = 2890^2 + 411^2 .

It is a cyclic number.

It is not a de Polignac number, because 8521021 - 2³ = 8521013 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 8521021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8521061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4260510 + 4260511.

It is an arithmetic number, because the mean of its divisors is an integer number (4260511).

Almost surely, 2^8521021 is an apocalyptic number.

It is an amenable number.

8521021 is a deficient number, since it is larger than the sum of its proper divisors (1).

8521021 is an equidigital number, since it uses as much as digits as its factorization.

8521021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 160, while the sum is 19.

The square root of 8521021 is about 2919.0787930441. The cubic root of 8521021 is about 204.2508528195.

Adding to 8521021 its reverse (1201258), we get a palindrome (9722279).

The spelling of 8521021 in words is "eight million, five hundred twenty-one thousand, twenty-one".