• 158 can be written using four 4's:

158 has 4 divisors (see below), whose sum is σ = 240. Its totient is φ = 78.

The previous prime is 157. The next prime is 163. The reversal of 158 is 851.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 851 = 23 ⋅37.

It is a magnanimous number.

It is the 18-th Perrin number.

It is a Curzon number.

It is a plaindrome in base 5, base 8, base 10, base 11, base 12 and base 16.

It is a nialpdrome in base 6, base 13, base 14 and base 15.

It is a congruent number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38 + ... + 41.

It is an arithmetic number, because the mean of its divisors is an integer number (60).

158 is a deficient number, since it is larger than the sum of its proper divisors (82).

158 is an equidigital number, since it uses as much as digits as its factorization.

It is an anagram of its base 9 representation: 158 = (185)_{9}.

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

The sum of its prime factors is 81.

The product of its digits is 40, while the sum is 14.

The square root of 158 is about 12.5698050900. The cubic root of 158 is about 5.4061201758.

Subtracting from 158 its sum of digits (14), we obtain a square (144 = 12^{2}).

It can be divided in two parts, 15 and 8, that multiplied together give a triangular number (120 = T_{15}).

The spelling of 158 in words is "one hundred fifty-eight", and thus it is an aban number.

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