666973440 has 360 divisors, whose sum is σ = 2730456960. Its totient is φ = 152285184.

The previous prime is 666973429. The next prime is 666973469. The reversal of 666973440 is 44379666.

It is a tau number, because it is divible by the number of its divisors (360).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 725301 + ... + 726219.

Almost surely, 2^666973440 is an apocalyptic number.

666973440 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 666973440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1365228480).

666973440 is an abundant number, since it is smaller than the sum of its proper divisors (2063483520).

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

666973440 is an equidigital number, since it uses as much as digits as its factorization.

666973440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 959 (or 936 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 45.

The square root of 666973440 is about 25825.8289315174. The cubic root of 666973440 is about 873.7144397840.

The spelling of 666973440 in words is "six hundred sixty-six million, nine hundred seventy-three thousand, four hundred forty".