1533

1533 = 3 x 7 x 73. The concatenation of the prime factors of 1533 is a palindrome  (A046452): 3773.

1533 is palindromic in base 2 (binary) (A048700): 10111111101.

1533 is a divisor of 64³ - 1.

1533 is 21 x the 21st prime (73) (A033286).

1533 is a number n such that 4n - 1, 8n - 1, and 16n - 1 are primes (A101790), as are 2n + 1, 4n + 1, and 6n + 1 (A124408).

Source: On-Line Encyclopedia of Integer Sequences