666860040 has 480 divisors, whose sum is σ = 2827218240. Its totient is φ = 138568320.

The previous prime is 666860023. The next prime is 666860069. The reversal of 666860040 is 40068666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 666859977 and 666860004.

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 119 ways as a sum of consecutive naturals, for example, 60623635 + ... + 60623645.

It is an arithmetic number, because the mean of its divisors is an integer number (5890038).

Almost surely, 2^666860040 is an apocalyptic number.

666860040 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 666860040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1413609120).

666860040 is an abundant number, since it is smaller than the sum of its proper divisors (2160358200).

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

666860040 is an equidigital number, since it uses as much as digits as its factorization.

666860040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67 (or 28 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The square root of 666860040 is about 25823.6333617096. The cubic root of 666860040 is about 873.6649201543.

The spelling of 666860040 in words is "six hundred sixty-six million, eight hundred sixty thousand, forty".