666505268 has 36 divisors (see below), whose sum is σ = 1380691620. Its totient is φ = 279649920.

The previous prime is 666505267. The next prime is 666505277. The reversal of 666505268 is 862505666.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 382515364 + 283989904 = 19558^2 + 16852^2 .

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666505267) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 46673 + ... + 59256.

It is an arithmetic number, because the mean of its divisors is an integer number (38352545).

Almost surely, 2^666505268 is an apocalyptic number.

It is an amenable number.

666505268 is an abundant number, since it is smaller than the sum of its proper divisors (714186352).

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

666505268 is a wasteful number, since it uses less digits than its factorization.

666505268 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105968 (or 105955 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 44.

The square root of 666505268 is about 25816.7633137851. The cubic root of 666505268 is about 873.5099616853.

The spelling of 666505268 in words is "six hundred sixty-six million, five hundred five thousand, two hundred sixty-eight".