666465856 has 63 divisors (see below), whose sum is σ = 1541783937. Its totient is φ = 285008640.

The previous prime is 666465827. The next prime is 666465859. The reversal of 666465856 is 658564666.

It is a happy number.

The square root of 666465856 is 25816.

It is a perfect power (a square), and thus also a powerful number.

666465856 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 213627456 + 452838400 = 14616^2 + 21280^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666465859) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1445466 + ... + 1445926.

Almost surely, 2^666465856 is an apocalyptic number.

666465856 is the 25816-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666465856

666465856 is an abundant number, since it is smaller than the sum of its proper divisors (875318081).

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

666465856 is an frugal number, since it uses more digits than its factorization.

666465856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 948 (or 470 counting only the distinct ones).

The product of its digits is 6220800, while the sum is 52.

The cubic root of 666465856 is about 873.4927437903.

The spelling of 666465856 in words is "six hundred sixty-six million, four hundred sixty-five thousand, eight hundred fifty-six".