30891 has 8 divisors (see below), whose sum is σ = 47104. Its totient is φ = 17640.
The previous prime is 30881. The next prime is 30893. The reversal of 30891 is 19803.
It is a sphenic number, since it is the product of 3 distinct primes.
It is not a de Polignac number, because 30891 - 25 = 30859 is a prime.
It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 1471 = 30891 / (3 + 0 + 8 + 9 + 1).
It is a Duffinian number.
It is a plaindrome in base 16.
It is not an unprimeable number, because it can be changed into a prime (30893) by changing a digit.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 715 + ... + 756.
It is an arithmetic number, because the mean of its divisors is an integer number (5888).
230891 is an apocalyptic number.
30891 is a deficient number, since it is larger than the sum of its proper divisors (16213).
30891 is a wasteful number, since it uses less digits than its factorization.
30891 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 1481.
The product of its (nonzero) digits is 216, while the sum is 21.
The square root of 30891 is about 175.7583568426. The cubic root of 30891 is about 31.3769449544.
The spelling of 30891 in words is "thirty thousand, eight hundred ninety-one".
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