30813 has 4 divisors (see below), whose sum is σ = 41088. Its totient is φ = 20540.

The previous prime is 30809. The next prime is 30817. The reversal of 30813 is 31803.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 31803 = 3 ⋅10601.

It is an interprime number because it is at equal distance from previous prime (30809) and next prime (30817).

It is a cyclic number.

It is not a de Polignac number, because 30813 - 2² = 30809 is a prime.

It is a super-3 number, since 3×30813³ = 87765373733391, which contains 333 as substring.

It is a D-number.

It is a Curzon number.

It is a plaindrome in base 7.

It is a junction number, because it is equal to n+sod(n) for n = 30792 and 30801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30817) 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, 5133 + ... + 5138.

It is an arithmetic number, because the mean of its divisors is an integer number (10272).

2³⁰⁸¹³ is an apocalyptic number.

It is an amenable number.

30813 is a deficient number, since it is larger than the sum of its proper divisors (10275).

30813 is a wasteful number, since it uses less digits than its factorization.

30813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10274.

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 30813 is about 175.5363210279. The cubic root of 30813 is about 31.3505136906.

Subtracting 30813 from its reverse (31803), we obtain a triangular number (990 = T₄₄).

It can be divided in two parts, 308 and 13, that multiplied together give a palindrome (4004).

The spelling of 30813 in words is "thirty thousand, eight hundred thirteen".