66990 has 64 divisors (see below), whose sum is σ = 207360. Its totient is φ = 13440.

The previous prime is 66977. The next prime is 67003. The reversal of 66990 is 9966.

It is an interprime number because it is at equal distance from previous prime (66977) and next prime (67003).

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2296 + ... + 2324.

It is an arithmetic number, because the mean of its divisors is an integer number (3240).

2⁶⁶⁹⁹⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (103680).

66990 is an abundant number, since it is smaller than the sum of its proper divisors (140370).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66990 is a wasteful number, since it uses less digits than its factorization.

66990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57.

The product of its (nonzero) digits is 2916, while the sum is 30.

The square root of 66990 is about 258.8242647048. The cubic root of 66990 is about 40.6134602332.

It can be divided in two parts, 6 and 6990, that added together give a palindrome (6996).

The spelling of 66990 in words is "sixty-six thousand, nine hundred ninety".