38 (number)

← 37 38 39 →
← 30 31 32 33 34 35 36 37 38 39 → List of numbers Integers ← 0 10 20 30 40 50 60 70 80 90 →
Cardinal	thirty-eight
Ordinal	38th (thirty-eighth)
Factorization	2 × 19
Divisors	1, 2, 19, 38
Greek numeral	ΛΗ´
Roman numeral	XXXVIII, xxxviii
Binary	1001102
Ternary	11023
Senary	1026
Octal	468
Duodecimal	3212
Hexadecimal	2616

38 (thirty-eight) is the natural number following 37 and preceding 39.

In mathematics

• specifically, the 11th discrete Semiprime, it being the 7th of the form (2.q).
• the first member of the third cluster of two discrete semiprimes 38, 39 the next such cluster is 57, 58.
• with an aliquot sum of 22 in an aliquot sequence of five composite numbers (38,22,14,10,8,7,1,0) to the Prime in the 7-aliquot tree. 38 is the first semiprime within a chain of 4 semiprimes in its aliquot sequence (38,22,14,10). The next semiprime with a four semiprime chain is 166.
• 38! − 1 yields 523022617466601111760007224100074291199999999 which is the 16th factorial prime.
• There is no answer to the equation φ(x) = 38, making 38 a nontotient.
• 38 is the sum of the squares of the first three primes.
• 37 and 38 are the first pair of consecutive positive integers not divisible by any of their digits.
• 38 is the largest even number which cannot be written as the sum of two odd composite numbers.
• The sum of each row of the only non-trivial (order 3) magic hexagon is 38.