141

a centered pentagonal number.
the sum of the sums of the divisors of the first 13 positive integers.
the second n to give a prime Cullen number (of the form n2n + 1).
an undulating number in base 10, with the previous being 131, and the next being 151.
the sixth hendecagonal (11-gonal) number.
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