66651 has 8 divisors (see below), whose sum is σ = 95760. Its totient is φ = 40992.

The previous prime is 66643. The next prime is 66653. The reversal of 66651 is 15666.

66651 is an esthetic number in base 6, because in such base its adjacent digits differ by 1.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66651 - 2³ = 66643 is a prime.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (66653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 816 + ... + 893.

It is an arithmetic number, because the mean of its divisors is an integer number (11970).

2⁶⁶⁶⁵¹ is an apocalyptic number.

66651 is a deficient number, since it is larger than the sum of its proper divisors (29109).

66651 is a wasteful number, since it uses less digits than its factorization.

66651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1725.

The product of its digits is 1080, while the sum is 24.

The square root of 66651 is about 258.1685495950. The cubic root of 66651 is about 40.5448367939.

It can be divided in two parts, 6665 and 1, that added together give a palindrome (6666).

The spelling of 66651 in words is "sixty-six thousand, six hundred fifty-one".