Search a number
28957 = 231259
BaseRepresentation
bin111000100011101
31110201111
413010131
51411312
6342021
7150265
oct70435
943644
1028957
111a835
1214911
1310246
14a7a5
1588a7
hex711d

28957 has 4 divisors (see below), whose sum is σ = 30240. Its totient is φ = 27676.

The previous prime is 28949. The next prime is 28961. The reversal of 28957 is 75982.

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: 75982 = 237991.

It is a cyclic number.

It is not a de Polignac number, because 28957 - 23 = 28949 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28927) 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, 607 + ... + 652.

It is an arithmetic number, because the mean of its divisors is an integer number (7560).

228957 is an apocalyptic number.

It is an amenable number.

28957 is a deficient number, since it is larger than the sum of its proper divisors (1283).

28957 is a wasteful number, since it uses less digits than its factorization.

28957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1282.

The product of its digits is 5040, while the sum is 31.

The square root of 28957 is about 170.1675644769. The cubic root of 28957 is about 30.7079757312.

It can be divided in two parts, 28 and 957, that multiplied together give a triangular number (26796 = T231).

The spelling of 28957 in words is "twenty-eight thousand, nine hundred fifty-seven".

Divisors: 1 23 1259 28957