85170021 has 16 divisors (see below), whose sum is σ = 115105344. Its totient is φ = 56012544.

The previous prime is 85170011. The next prime is 85170037. The reversal of 85170021 is 12007158.

It is not a de Polignac number, because 85170021 - 2⁶ = 85169957 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 85169973 and 85170000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (85170011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 93450 + ... + 94356.

It is an arithmetic number, because the mean of its divisors is an integer number (7194084).

Almost surely, 2^85170021 is an apocalyptic number.

It is an amenable number.

85170021 is a deficient number, since it is larger than the sum of its proper divisors (29935323).

85170021 is a wasteful number, since it uses less digits than its factorization.

85170021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1300.

The product of its (nonzero) digits is 560, while the sum is 24.

The square root of 85170021 is about 9228.7605343296. The cubic root of 85170021 is about 439.9759301571.

Adding to 85170021 its reverse (12007158), we get a palindrome (97177179).

The spelling of 85170021 in words is "eighty-five million, one hundred seventy thousand, twenty-one".