Search a number
BaseRepresentation
bin111100010100001
31120100202
413202201
51442011
6354545
7156014
oct74241
946322
1030881
1121224
1215a55
1311096
14b37b
15923b
hex78a1

30881 has 2 divisors, whose sum is σ = 30882. Its totient is φ = 30880.

The previous prime is 30871. The next prime is 30893. The reversal of 30881 is 18803.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30625 + 256 = 175^2 + 16^2 .

It is an emirp because it is prime and its reverse (18803) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 30881 - 26 = 30817 is a prime.

It is a super-2 number, since 2×308812 = 1907272322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 30881.

It is not a weakly prime, because it can be changed into another prime (30841) 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 as a sum of consecutive naturals, namely, 15440 + 15441.

It is an arithmetic number, because the mean of its divisors is an integer number (15441).

230881 is an apocalyptic number.

It is an amenable number.

30881 is a deficient number, since it is larger than the sum of its proper divisors (1).

30881 is an equidigital number, since it uses as much as digits as its factorization.

30881 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 30881 is about 175.7299063905. The cubic root of 30881 is about 31.3735588191.

The spelling of 30881 in words is "thirty thousand, eight hundred eighty-one".