85511 has 4 divisors (see below), whose sum is σ = 86112. Its totient is φ = 84912.

The previous prime is 85487. The next prime is 85513. The reversal of 85511 is 11558.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 11558 = 2 ⋅5779.

It is a cyclic number.

It is not a de Polignac number, because 85511 - 2⁶ = 85447 is a prime.

It is a super-2 number, since 2×85511² = 14624262242, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (85513) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 50 + ... + 416.

It is an arithmetic number, because the mean of its divisors is an integer number (21528).

2⁸⁵⁵¹¹ is an apocalyptic number.

85511 is a deficient number, since it is larger than the sum of its proper divisors (601).

85511 is a wasteful number, since it uses less digits than its factorization.

85511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 600.

The product of its digits is 200, while the sum is 20.

The square root of 85511 is about 292.4226393424. The cubic root of 85511 is about 44.0562297635.

Subtracting from 85511 its sum of digits (20), we obtain a triangular number (85491 = T₄₁₃).

The spelling of 85511 in words is "eighty-five thousand, five hundred eleven".