8500021 has 2 divisors, whose sum is σ = 8500022. Its totient is φ = 8500020.

The previous prime is 8500007. The next prime is 8500027. The reversal of 8500021 is 1200058.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7365796 + 1134225 = 2714^2 + 1065^2 .

It is a cyclic number.

It is not a de Polignac number, because 8500021 - 2⁷ = 8499893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 8499968 and 8500004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8500027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4250010 + 4250011.

It is an arithmetic number, because the mean of its divisors is an integer number (4250011).

Almost surely, 2^8500021 is an apocalyptic number.

It is an amenable number.

8500021 is a deficient number, since it is larger than the sum of its proper divisors (1).

8500021 is an equidigital number, since it uses as much as digits as its factorization.

8500021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 8500021 is about 2915.4795488907. The cubic root of 8500021 is about 204.0829231639.

Adding to 8500021 its reverse (1200058), we get a palindrome (9700079).

The spelling of 8500021 in words is "eight million, five hundred thousand, twenty-one".