90817 has 4 divisors (see below), whose sum is σ = 91476. Its totient is φ = 90160.

The previous prime is 90803. The next prime is 90821. The reversal of 90817 is 71809.

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.

It can be written as a sum of positive squares in 2 ways, for example, as 65536 + 25281 = 256^2 + 159^2 .

It is a cyclic number.

It is not a de Polignac number, because 90817 - 2¹⁵ = 58049 is a prime.

It is a Duffinian number.

90817 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 90791 and 90800.

It is not an unprimeable number, because it can be changed into a prime (90847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34 + ... + 427.

It is an arithmetic number, because the mean of its divisors is an integer number (22869).

2⁹⁰⁸¹⁷ is an apocalyptic number.

It is an amenable number.

90817 is a deficient number, since it is larger than the sum of its proper divisors (659).

90817 is a wasteful number, since it uses less digits than its factorization.

90817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 658.

The product of its (nonzero) digits is 504, while the sum is 25.

The square root of 90817 is about 301.3585903869. The cubic root of 90817 is about 44.9492431829.

The spelling of 90817 in words is "ninety thousand, eight hundred seventeen".