666387280 has 120 divisors (see below), whose sum is σ = 1751459328. Its totient is φ = 235243008.

The previous prime is 666387277. The next prime is 666387287. The reversal of 666387280 is 82783666.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is a self number, because there is not a number n which added to its sum of digits gives 666387280.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666387287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 309889 + ... + 312031.

Almost surely, 2^666387280 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 666387280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (875729664).

666387280 is an abundant number, since it is smaller than the sum of its proper divisors (1085072048).

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

666387280 is a wasteful number, since it uses less digits than its factorization.

666387280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2205 (or 2186 counting only the distinct ones).

The product of its (nonzero) digits is 580608, while the sum is 46.

The square root of 666387280 is about 25814.4781082245. The cubic root of 666387280 is about 873.4584143180.

The spelling of 666387280 in words is "six hundred sixty-six million, three hundred eighty-seven thousand, two hundred eighty".