85815217 has 2 divisors, whose sum is σ = 85815218. Its totient is φ = 85815216.

The previous prime is 85815211. The next prime is 85815239. The reversal of 85815217 is 71251858.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 76055841 + 9759376 = 8721^2 + 3124^2 .

It is a cyclic number.

It is not a de Polignac number, because 85815217 - 2¹⁵ = 85782449 is a prime.

It is not a weakly prime, because it can be changed into another prime (85815211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42907608 + 42907609.

It is an arithmetic number, because the mean of its divisors is an integer number (42907609).

Almost surely, 2^85815217 is an apocalyptic number.

It is an amenable number.

85815217 is a deficient number, since it is larger than the sum of its proper divisors (1).

85815217 is an equidigital number, since it uses as much as digits as its factorization.

85815217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22400, while the sum is 37.

The square root of 85815217 is about 9263.6503064397. The cubic root of 85815217 is about 441.0841326999.

The spelling of 85815217 in words is "eighty-five million, eight hundred fifteen thousand, two hundred seventeen".