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1998 = 23337
BaseRepresentation
bin11111001110
32202000
4133032
530443
613130
75553
oct3716
92660
101998
111557
1211a6
13ba9
14a2a
158d3
hex7ce

1998 has 16 divisors (see below), whose sum is σ = 4560. Its totient is φ = 648.

The previous prime is 1997. The next prime is 1999. The reversal of 1998 is 8991.

Adding to 1998 its sum of digits (27), we get a square (2025 = 452).

It can be divided in two parts, 1 and 998, that added together give a palindrome (999).

1998 is nontrivially palindromic in base 14.

1998 is an esthetic number in base 13, because in such base its adjacent digits differ by 1.

It is an interprime number because it is at equal distance from previous prime (1997) and next prime (1999).

It is a Harshad number since it is a multiple of its sum of digits (27).

1998 is an undulating number in base 14.

It is a plaindrome in base 11 and base 16.

It is a nialpdrome in base 7 and base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1993) 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, 36 + ... + 72.

It is an arithmetic number, because the mean of its divisors is an integer number (285).

1998 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 1998, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2280).

1998 is an abundant number, since it is smaller than the sum of its proper divisors (2562).

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

1998 is a wasteful number, since it uses less digits than its factorization.

1998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48 (or 42 counting only the distinct ones).

The product of its digits is 648, while the sum is 27.

The square root of 1998 is about 44.6989932773. The cubic root of 1998 is about 12.5950093614.

The spelling of 1998 in words is "one thousand, nine hundred ninety-eight".

Divisors: 1 2 3 6 9 18 27 37 54 74 111 222 333 666 999 1998