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BaseRepresentation
bin11001100110
32020200
4121212
523023
611330
74530
oct3146
92220
101638
11125a
12b46
13990
14850
15743
hex666

1638 has 24 divisors (see below), whose sum is σ = 4368. Its totient is φ = 432.

The previous prime is 1637. The next prime is 1657. The reversal of 1638 is 8361.

1638 divided by its sum of digits (18) gives a triangular number (91 = T13).

Adding to 1638 its reverse (8361), we get a palindrome (9999).

It can be divided in two parts, 163 and 8, that added together give a palindrome (171).

1638 is nontrivially palindromic in base 16.

1638 is an esthetic number in base 4, because in such base its adjacent digits differ by 1.

It is a harmonic number, since the harmonic mean of its divisors is an integer.

1638 is an admirable number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an alternating number because its digits alternate between odd and even.

1638 is an undulating number in base 4.

It is a Curzon number.

1638 is a nontrivial repdigit in base 16.

It is a plaindrome in base 11 and base 16.

It is a nialpdrome in base 9, base 13, base 14, base 15 and base 16.

It is a zygodrome in base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 1638.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1637) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 120 + ... + 132.

It is an arithmetic number, because the mean of its divisors is an integer number (182).

21638 is an apocalyptic number.

1638 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2184).

1638 is an abundant number, since it is smaller than the sum of its proper divisors (2730).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1638 is a wasteful number, since it uses less digits than its factorization.

1638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28 (or 25 counting only the distinct ones).

The product of its digits is 144, while the sum is 18.

The square root of 1638 is about 40.4722126897. The cubic root of 1638 is about 11.7879413344.

The spelling of 1638 in words is "one thousand, six hundred thirty-eight".