85165821 has 24 divisors (see below), whose sum is σ = 134663256. Its totient is φ = 51546240.

The previous prime is 85165811. The next prime is 85165841. The reversal of 85165821 is 12856158.

It can be written as a sum of positive squares in 4 ways, for example, as 617796 + 84548025 = 786^2 + 9195^2 .

It is not a de Polignac number, because 85165821 - 2⁷ = 85165693 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (85165811) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1171 + ... + 13103.

It is an arithmetic number, because the mean of its divisors is an integer number (5610969).

Almost surely, 2^85165821 is an apocalyptic number.

It is an amenable number.

85165821 is a deficient number, since it is larger than the sum of its proper divisors (49497435).

85165821 is a wasteful number, since it uses less digits than its factorization.

85165821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12013 (or 12010 counting only the distinct ones).

The product of its digits is 19200, while the sum is 36.

The square root of 85165821 is about 9228.5329820075. The cubic root of 85165821 is about 439.9686978420.

The spelling of 85165821 in words is "eighty-five million, one hundred sixty-five thousand, eight hundred twenty-one".