666615456 has 144 divisors (see below), whose sum is σ = 2149187040. Its totient is φ = 194296320.

The previous prime is 666615451. The next prime is 666615491. The reversal of 666615456 is 654516666.

It is a tau number, because it is divible by the number of its divisors (144).

It is not an unprimeable number, because it can be changed into a prime (666615451) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 66451 + ... + 75821.

It is an arithmetic number, because the mean of its divisors is an integer number (14924910).

Almost surely, 2^666615456 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 666615456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1074593520).

666615456 is an abundant number, since it is smaller than the sum of its proper divisors (1482571584).

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

666615456 is a wasteful number, since it uses less digits than its factorization.

666615456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9419 (or 9408 counting only the distinct ones).

The product of its digits is 777600, while the sum is 45.

The square root of 666615456 is about 25818.8972653752. The cubic root of 666615456 is about 873.5580958445.

It can be divided in two parts, 6666 and 15456, that added together give a palindrome (22122).

The spelling of 666615456 in words is "six hundred sixty-six million, six hundred fifteen thousand, four hundred fifty-six".