• 98 can be written using four 4's:

See also 113.

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98 has 6 divisors (see below), whose sum is σ = 171. Its totient is φ = 42.

The previous prime is 97. The next prime is 101. The reversal of 98 is 89.

98 = 1⁴ + 2⁴ + 3⁴.

98 is nontrivially palindromic in base 5, base 6 and base 13.

98 is an esthetic number in base 5 and base 10, because in such bases its adjacent digits differ by 1.

It can be written as a sum of positive squares in only one way, i.e., 49 + 49 = 7^2 + 7^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=7.

It is a magnanimous number.

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

It is a Duffinian number.

98 is an undulating number in base 5 and base 6.

Its product of digits (72) is a multiple of the sum of its prime divisors (9).

It is a Curzon number.

98 is a nontrivial repdigit in base 13.

It is a plaindrome in base 9, base 11, base 13 and base 15.

It is a nialpdrome in base 7, base 10, base 12, base 13, base 14 and base 16.

It is a zygodrome in base 13.

It is a pernicious number, because its binary representation contains a prime number (3) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 11 + ... + 17.

98 is a deficient number, since it is larger than the sum of its proper divisors (73).

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

With its successor (99) it forms an eRAP, since the sums of their prime factors are consecutive (16 and 17).

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

The sum of its prime factors is 16 (or 9 counting only the distinct ones).

The product of its digits is 72, while the sum is 17.

The square root of 98 is about 9.8994949366. The cubic root of 98 is about 4.6104362921.

Subtracting from 98 its sum of digits (17), we obtain a 4-th power (81 = 3⁴).

Multiplying 98 by its product of digits (72), we get a square (7056 = 84²).

The spelling of 98 in words is "ninety-eight", and thus it is an aban number, an oban number, and an uban number.