666880 has 36 divisors (see below), whose sum is σ = 1600452. Its totient is φ = 266240.

The previous prime is 666871. The next prime is 666889. The reversal of 666880 is 88666.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (666871) and next prime (666889).

It can be written as a sum of positive squares in 2 ways, for example, as 215296 + 451584 = 464^2 + 672^2 .

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666889) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1020 + ... + 1540.

It is an arithmetic number, because the mean of its divisors is an integer number (44457).

2⁶⁶⁶⁸⁸⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (800226).

666880 is an abundant number, since it is smaller than the sum of its proper divisors (933572).

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

666880 is an equidigital number, since it uses as much as digits as its factorization.

666880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 542 (or 528 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 666880 is about 816.6272099312. The cubic root of 666880 is about 87.3673636715.

The spelling of 666880 in words is "six hundred sixty-six thousand, eight hundred eighty".