666954 has 40 divisors (see below), whose sum is σ = 1568160. Its totient is φ = 211464.

The previous prime is 666937. The next prime is 666959. The reversal of 666954 is 459666.

It is a happy number.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

Its product of digits (38880) is a multiple of the sum of its prime factors (216).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666959) by changing a digit.

666954 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3637 + ... + 3815.

It is an arithmetic number, because the mean of its divisors is an integer number (39204).

2⁶⁶⁶⁹⁵⁴ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666954, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (784080).

666954 is an abundant number, since it is smaller than the sum of its proper divisors (901206).

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

666954 is a wasteful number, since it uses less digits than its factorization.

666954 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216 (or 207 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 666954 is about 816.6725169858. The cubic root of 666954 is about 87.3705951103.

The spelling of 666954 in words is "six hundred sixty-six thousand, nine hundred fifty-four".