66658 has 4 divisors (see below), whose sum is σ = 99990. Its totient is φ = 33328.

The previous prime is 66653. The next prime is 66683. The reversal of 66658 is 85666.

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

It can be written as a sum of positive squares in only one way, i.e., 51529 + 15129 = 227^2 + 123^2 .

It is a plaindrome in base 13.

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

66658 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16663 + ... + 16666.

2⁶⁶⁶⁵⁸ is an apocalyptic number.

66658 is a deficient number, since it is larger than the sum of its proper divisors (33332).

66658 is a wasteful number, since it uses less digits than its factorization.

66658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33331.

The product of its digits is 8640, while the sum is 31.

The square root of 66658 is about 258.1821062738. The cubic root of 66658 is about 40.5462561471.

The spelling of 66658 in words is "sixty-six thousand, six hundred fifty-eight".