141 (number)

141 is:

• a centered pentagonal number.^[1]
• the sum of the sums of the divisors of the first 13 positive integers.^[2]
• the second n to give a prime Cullen number (of the form n2ⁿ + 1).^[3]
• the first three digits after the decimal point in the base 10 representation of pi (3.141592...)
• an undulating number in base 10, with the previous being 131, and the next being 151.
• the sixth hendecagonal (11-gonal) number.^[4]
• a semiprime: a product of two prime numbers, namely 3 and 47. Since those prime factors are Gaussian primes, this means that 141 is a Blum integer.
• a Hilbert prime
• Sometimes used as an acronym [1 representing A and 4 representing D] to stand for Anti Deforestation Action, often used by radical environmentalists