66806 has 4 divisors (see below), whose sum is σ = 100212. Its totient is φ = 33402.

The previous prime is 66797. The next prime is 66809. The reversal of 66806 is 60866.

It is a semiprime because it is the product of two primes.

It is a plaindrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16700 + ... + 16703.

It is an arithmetic number, because the mean of its divisors is an integer number (25053).

2⁶⁶⁸⁰⁶ is an apocalyptic number.

66806 is a deficient number, since it is larger than the sum of its proper divisors (33406).

66806 is a wasteful number, since it uses less digits than its factorization.

66806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33405.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 66806 is about 258.4685667543. The cubic root of 66806 is about 40.5762420962.

The spelling of 66806 in words is "sixty-six thousand, eight hundred six".