90819 has 6 divisors (see below), whose sum is σ = 131196. Its totient is φ = 60540.

The previous prime is 90803. The next prime is 90821. The reversal of 90819 is 91809.

It is not a de Polignac number, because 90819 - 2⁴ = 90803 is a prime.

It is a super-2 number, since 2×90819² = 16496181522, which contains 22 as substring.

90819 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 90792 and 90801.

It is not an unprimeable number, because it can be changed into a prime (90019) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5037 + ... + 5054.

It is an arithmetic number, because the mean of its divisors is an integer number (21866).

2⁹⁰⁸¹⁹ is an apocalyptic number.

90819 is a deficient number, since it is larger than the sum of its proper divisors (40377).

90819 is a wasteful number, since it uses less digits than its factorization.

90819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10097 (or 10094 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 27.

The square root of 90819 is about 301.3619086746. The cubic root of 90819 is about 44.9495731426.

Subtracting 90819 from its reverse (91809), we obtain a triangular number (990 = T₄₄).

It can be divided in two parts, 90 and 819, that added together give a palindrome (909).

The spelling of 90819 in words is "ninety thousand, eight hundred nineteen".