666612720 has 320 divisors, whose sum is σ = 2487936000. Its totient is φ = 163482624.

The previous prime is 666612719. The next prime is 666612743. The reversal of 666612720 is 27216666.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1518261 + ... + 1518699.

It is an arithmetic number, because the mean of its divisors is an integer number (7774800).

Almost surely, 2^666612720 is an apocalyptic number.

666612720 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 666612720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1243968000).

666612720 is an abundant number, since it is smaller than the sum of its proper divisors (1821323280).

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

666612720 is a wasteful number, since it uses less digits than its factorization.

666612720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 517 (or 505 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 36.

The square root of 666612720 is about 25818.8442808736. The cubic root of 666612720 is about 873.5569007236.

The spelling of 666612720 in words is "six hundred sixty-six million, six hundred twelve thousand, seven hundred twenty".