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6445 = 51289
BaseRepresentation
bin1100100101101
322211201
41210231
5201240
645501
724535
oct14455
98751
106445
11492a
123891
132c1a
1424c5
151d9a
hex192d

6445 has 4 divisors (see below), whose sum is σ = 7740. Its totient is φ = 5152.

The previous prime is 6427. The next prime is 6449. The reversal of 6445 is 5446.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3844 + 2601 = 62^2 + 51^2 .

It is a cyclic number.

It is not a de Polignac number, because 6445 - 27 = 6317 is a prime.

It is a plaindrome in base 8.

It is a nialpdrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6449) 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, 640 + ... + 649.

It is an arithmetic number, because the mean of its divisors is an integer number (1935).

26445 is an apocalyptic number.

It is an amenable number.

6445 is a deficient number, since it is larger than the sum of its proper divisors (1295).

6445 is a wasteful number, since it uses less digits than its factorization.

6445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1294.

The product of its digits is 480, while the sum is 19.

The square root of 6445 is about 80.2807573457. The cubic root of 6445 is about 18.6097686383.

Subtracting from 6445 its reverse (5446), we obtain a palindrome (999).

The spelling of 6445 in words is "six thousand, four hundred forty-five".

Divisors: 1 5 1289 6445