666533280 has 288 divisors, whose sum is σ = 2587588416. Its totient is φ = 143302656.

The previous prime is 666533279. The next prime is 666533293. The reversal of 666533280 is 82335666.

It is a happy number.

It is a super-2 number, since 2×666533280² = 888533226695116800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 399007 + ... + 400673.

It is an arithmetic number, because the mean of its divisors is an integer number (8984682).

Almost surely, 2^666533280 is an apocalyptic number.

666533280 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666533280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1293794208).

666533280 is an abundant number, since it is smaller than the sum of its proper divisors (1921055136).

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

666533280 is a wasteful number, since it uses less digits than its factorization.

666533280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1716 (or 1701 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 39.

The square root of 666533280 is about 25817.3058238074. The cubic root of 666533280 is about 873.5221988571.

The spelling of 666533280 in words is "six hundred sixty-six million, five hundred thirty-three thousand, two hundred eighty".