666819522 has 48 divisors (see below), whose sum is σ = 1468916280. Its totient is φ = 218578176.

The previous prime is 666819511. The next prime is 666819523. The reversal of 666819522 is 225918666.

It can be written as a sum of positive squares in 4 ways, for example, as 666724041 + 95481 = 25821^2 + 309^2 .

It is not an unprimeable number, because it can be changed into a prime (666819523) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 668328 + ... + 669324.

Almost surely, 2^666819522 is an apocalyptic number.

666819522 is an abundant number, since it is smaller than the sum of its proper divisors (802096758).

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

666819522 is a wasteful number, since it uses less digits than its factorization.

666819522 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1587 (or 1584 counting only the distinct ones).

The product of its digits is 311040, while the sum is 45.

The square root of 666819522 is about 25822.8488358663. The cubic root of 666819522 is about 873.6472253508.

The spelling of 666819522 in words is "six hundred sixty-six million, eight hundred nineteen thousand, five hundred twenty-two".