portrait: 87

87 is: the sum of the squares of the first four primes (87 = 22 + 32 + 52 + 72). the sum of the sums of the divisors of the first 10 positive integers. the thirtieth semiprime, and the twenty-sixth distinct semiprime and the eighth of the form (3.q). together with 85 and 86,[4] forms the last semiprime in the 2nd cluster of three consecutive semiprimes; the first comprising 33, 34, 35. with an aliquot sum of 33; itself a semiprime, within an aliquot sequence of five composite numbers (87,33,15,9,4,3,1,0) to the Prime in the 3-aliquot tree. 5! - 4! - 3! - 2! - 1! = 87 the last two decimal digits of Graham's number.