It is a semiprime because it is the product of two primes.
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-66551 is a prime.
It is a Duffinian number.
It is a plaindrome in base 9 and base 15.
It is a nialpdrome in base 10.
It is a congruent number.
266551 is an apocalyptic number.
66551 is a gapful number since it is divisible by the number (61) formed by its first and last digit.
66551 is a wasteful number, since it uses less digits than its factorization.
66551 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 1152.
The square root of 66551 is about 257.9748049713. The cubic root of 66551 is about 40.5245494610.
The spelling of 66551 in words is "sixty-six thousand, five hundred fifty-one".