400 (number) + 61 + 67), strictly non-palindromic number 440 = 2 × 5 × 11, the sum of the first seventeen prime numbers, Harshad number, 441 = 3 × 7 = 21 442 = 2 × 13 × 17, sphenic number, sum of eight consecutive primes (41 + 43 + 47 + 53 + 59 + 61 + 67 + 71) A prime number, Sophie Germain prime, Chen prime, Eisenstein prime with no imaginary part, Mertens function sets new low of -9, which stands until 659. 444 = 2 × 3 × 37, refactorable number, Harshad number. 445 = 5 ×
400 (number) = 2 × 101, Mertens function returns 0, nontotient, noncototient. 405 = 3 × 5, Mertens function returns 0, Harshad number; 406 = 2 × 7 × 29, sphenic number, triangular number, centered nonagonal number, nontotient 407 = 11 × 37, 408 = 2 × 3 × 17 409 is a prime number, Chen prime, centered triangular number. 410 = 2 × 5 × 41, sphenic number, sum of six consecutive primes (59 + 61 + 67 + 71 + 73 + 79), nontotient, Harshad number 411 = 3 × 137, self number, 412 = 2 × 103, nontotient, noncototient,