85811815 has 4 divisors (see below), whose sum is σ = 102974184. Its totient is φ = 68649448.

The previous prime is 85811777. The next prime is 85811849. The reversal of 85811815 is 51811858.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 85811815 - 2⁹ = 85811303 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8581177 + ... + 8581186.

It is an arithmetic number, because the mean of its divisors is an integer number (25743546).

Almost surely, 2^85811815 is an apocalyptic number.

85811815 is a deficient number, since it is larger than the sum of its proper divisors (17162369).

85811815 is a wasteful number, since it uses less digits than its factorization.

85811815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17162368.

The product of its digits is 12800, while the sum is 37.

The square root of 85811815 is about 9263.4666836989. The cubic root of 85811815 is about 441.0783039432.

The spelling of 85811815 in words is "eighty-five million, eight hundred eleven thousand, eight hundred fifteen".