30913 has 4 divisors (see below), whose sum is σ = 32560.
Its totient is φ = 29268.
The previous prime is 30911. The next prime is 30931. The reversal of 30913 is 31903.
Subtracting 30913 from its reverse (31903), we obtain a triangular number (990 = T44).
It is a happy number.
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: 31903 = 61 ⋅523.
It is a cyclic number.
It is not a de Polignac number, because 30913 - 21 = 30911 is a prime.
It is a super-2 number, since 2×309132 = 1911227138, which contains 22 as substring.
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (30911) 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, 795 + ... + 832.
It is an arithmetic number, because the mean of its divisors is an integer number (8140).
230913 is an apocalyptic number.
It is an amenable number.
30913 is a deficient number, since it is larger than the sum of its proper divisors (1647).
30913 is a wasteful number, since it uses less digits than its factorization.
30913 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 1646.
The product of its (nonzero) digits is 81, while the sum is 16.
The square root of 30913 is about 175.8209316322.
The cubic root of 30913 is about 31.3843918805.
The spelling of 30913 in words is "thirty thousand, nine hundred thirteen".