85000021 has 2 divisors, whose sum is σ = 85000022. Its totient is φ = 85000020.

The previous prime is 85000009. The next prime is 85000037. The reversal of 85000021 is 12000058.

It is a happy number.

It is an a-pointer prime, because the next prime (85000037) can be obtained adding 85000021 to its sum of digits (16).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 63377521 + 21622500 = 7961^2 + 4650^2 .

It is a cyclic number.

It is not a de Polignac number, because 85000021 - 2¹¹ = 84997973 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 84999959 and 85000004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85000081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42500010 + 42500011.

It is an arithmetic number, because the mean of its divisors is an integer number (42500011).

Almost surely, 2^85000021 is an apocalyptic number.

It is an amenable number.

85000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

85000021 is an equidigital number, since it uses as much as digits as its factorization.

85000021 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 85000021 is about 9219.5455961777. The cubic root of 85000021 is about 439.6830034250.

Adding to 85000021 its reverse (12000058), we get a palindrome (97000079).

The spelling of 85000021 in words is "eighty-five million, twenty-one", and thus it is an aban number and an uban number.