129

Properties by base:

More about this number at Positiv Integers and Number Empire.

The number is not a prime.

Its 2 (2 unique) factors are:
3
43

Its 4 divisors are:
1
3
43
129
Its aliquote sum is:
47
makeing it a deficient number.

As Unicode codepoint (since version 1.1) this number represents this character: HIGH OCTET PRESET (HOP) in Latin-1 Supplement (Source: https://unicode-api.aaronluna.dev/v1/codepoints/81?show_props=Basic); HTML: 

In the work of Johann Sebastian Bach BWV 129 is Gelobet sei der Herr, mein Gott

The number appears at position 499 of the decimal digits of π surrounded by
2489122793818301194912983367336244065664308 Source: The Pi-Search Page

Computations done with Math::BigInt 1.999811 and Math::Pari 2.030523 based on PARI/GP 2.11.3 (elapsed: 1767.093ms; cpu: 89.7640000000001ms)