155 (number)
Natural number
From Wikipedia, the free encyclopedia
155 (one hundred [and] fifty-five) is the natural number following 154 and preceding 156.
Cardinalone hundred fifty-five
Ordinal155th
(one hundred fifty-fifth)
(one hundred fifty-fifth)
Factorization5 Ã 31
Divisors1, 5, 31, 155
| ||||
|---|---|---|---|---|
| Cardinal | one hundred fifty-five | |||
| Ordinal | 155th (one hundred fifty-fifth) | |||
| Factorization | 5 Ã 31 | |||
| Divisors | 1, 5, 31, 155 | |||
| Greek numeral | ΡÎδ | |||
| Roman numeral | CLV, clv | |||
| Binary | 100110112 | |||
| Ternary | 122023 | |||
| Senary | 4156 | |||
| Octal | 2338 | |||
| Duodecimal | 10B12 | |||
| Hexadecimal | 9B16 | |||
In mathematics
155 is:
- a composite number
- a semiprime.
- a deficient number, since 1+5+31=37<155.
- odious, since its binary expansion has a total of 5 ones in it.
- Its prime factorization is 5*31, and the sum of the prime numbers between 5 and 31, inclusively, is 155.
There are 155 primitive permutation groups of degree 81. OEIS: A000019
If one adds up all the primes from the least through the greatest prime factors of 155, that is, 5 and 31, the result is 155. (sequence A055233 in the OEIS) Only three other "small" semiprimes (10, 39, and 371) share this attribute.
Other uses
- 155 is the airline code for DHL Aviation.[1]
